Theorem: alternatingGroup.isPreprimitive_of_stabilizer_lt (Jordan/AlternatingMaximal.lean)

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
⊢ IsPreprimitive (↥G) α
Tactic:
apply IsPreprimitive.mk
State after:
case has_trivial_blocks'
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
⊢ ∀ {B : Set α}, IsBlock (↥G) B → IsTrivialBlock B

State before:
case has_trivial_blocks'
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
⊢ ∀ {B : Set α}, IsBlock (↥G) B → IsTrivialBlock B
Tactic:
intro B hB
State after:
case has_trivial_blocks'
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
⊢ IsTrivialBlock B

State before:
case has_trivial_blocks'
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
⊢ IsTrivialBlock B
Tactic:
unfold IsTrivialBlock
State after:
case has_trivial_blocks'
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
⊢ Set.Subsingleton B ∨ B = ⊤

State before:
case has_trivial_blocks'
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
⊢ Set.Subsingleton B ∨ B = ⊤
Tactic:
rw [or_iff_not_imp_left]
State after:
case has_trivial_blocks'
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
⊢ ¬Set.Subsingleton B → B = ⊤

State before:
case has_trivial_blocks'
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
⊢ ¬Set.Subsingleton B → B = ⊤
Tactic:
intro hB'
State after:
case has_trivial_blocks'
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
⊢ B = ⊤

State before:
case has_trivial_blocks'
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
⊢ B = ⊤
Tactic:
obtain ⟨a, ha, ha'⟩ := Set.not_subset_iff_exists_mem_not_mem.mp
  fun h => hB' ((hB_not_le_sc B hB) h)
State after:
case has_trivial_blocks'.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∉ sᶜ
⊢ B = ⊤

State before:
case has_trivial_blocks'.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∉ sᶜ
⊢ B = ⊤
Tactic:
rw [Set.not_mem_compl_iff] at ha'
State after:
case has_trivial_blocks'.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
⊢ B = ⊤

State before:
case has_trivial_blocks'.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
⊢ B = ⊤
Tactic:
obtain ⟨b, hb, hb'⟩ := Set.not_subset_iff_exists_mem_not_mem.mp
  fun h => hB' ((hB_not_le_s B hB) h)
State after:
case has_trivial_blocks'.intro.intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∉ s
⊢ B = ⊤

State before:
case has_trivial_blocks'.intro.intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∉ s
⊢ B = ⊤
Tactic:
rw [← Set.mem_compl_iff] at hb'
State after:
case has_trivial_blocks'.intro.intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
⊢ B = ⊤

State before:
case has_trivial_blocks'.intro.intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
⊢ B = ⊤
Tactic:
rw [eq_top_iff]
State after:
case has_trivial_blocks'.intro.intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
⊢ ⊤ ≤ B

State before:
case has_trivial_blocks'.intro.intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
⊢ ⊤ ≤ B
Tactic:
intro x _
State after:
case has_trivial_blocks'.intro.intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
⊢ x ∈ B

State before:
case has_trivial_blocks'.intro.intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
⊢ x ∈ B
Tactic:
obtain ⟨b, hb⟩ := h1.nonempty
State after:
case has_trivial_blocks'.intro.intro.intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
⊢ x ∈ B

State before:
case has_trivial_blocks'.intro.intro.intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
⊢ x ∈ B
Tactic:
obtain ⟨⟨g, hg⟩, hgbx : g • b = x⟩ := exists_smul_eq G b x
State after:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ x ∈ B

State before:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ x ∈ B
Tactic:
suffices g • B = B by
  rw [← hgbx, ← this, Set.smul_mem_smul_set_iff]
  exact hsc_le_B hb
State after:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ g • B = B

State before:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ g • B = B
Tactic:
apply or_iff_not_imp_right.mp (IsBlock.def_one.mp hB ⟨g, hg⟩)
State after:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ ¬Disjoint ({ val := g, property := hg } • B) B

State before:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ ¬Disjoint ({ val := g, property := hg } • B) B
Tactic:
rw [Set.not_disjoint_iff_nonempty_inter]
State after:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ Set.Nonempty ({ val := g, property := hg } • B ∩ B)

State before:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ Set.Nonempty ({ val := g, property := hg } • B ∩ B)
Tactic:
change (g • B ∩ B).Nonempty
State after:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ Set.Nonempty (g • B ∩ B)

State before:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ Set.Nonempty (g • B ∩ B)
Tactic:
apply Set.ncard_pigeonhole
State after:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk.h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ Fintype.card α < Set.ncard (g • B) + Set.ncard B

State before:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk.h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ Fintype.card α < Set.ncard (g • B) + Set.ncard B
Tactic:
rw [← Nat.card_eq_fintype_card, ← Set.ncard_add_ncard_compl s]
State after:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk.h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ Set.ncard s + Set.ncard sᶜ < Set.ncard (g • B) + Set.ncard B

State before:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk.h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ Set.ncard s + Set.ncard sᶜ < Set.ncard (g • B) + Set.ncard B
Tactic:
apply Nat.lt_of_lt_of_le
State after:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk.h.a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ Set.ncard s + Set.ncard sᶜ < ?has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk.h.m

case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk.h.a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ ?has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk.h.m ≤ Set.ncard (g • B) + Set.ncard B

case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk.h.m
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ ℕ

State before:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk.h.a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ Set.ncard sᶜ + Set.ncard sᶜ ≤ Set.ncard (g • B) + Set.ncard B
Tactic:
apply Nat.add_le_add
State after:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk.h.a.h₁
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ Set.ncard sᶜ ≤ Set.ncard (g • B)

case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk.h.a.h₂
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ Set.ncard sᶜ ≤ Set.ncard B

State before:
case has_trivial_blocks'.intro.intro.intro.intro.intro.intro.mk.h.a.h₂
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b✝ : α
hb✝ : b✝ ∈ B
hb' : b✝ ∈ sᶜ
hsc_le_B : sᶜ ⊆ B
x : α
a✝ : x ∈ ⊤
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ G
hgbx : g • b = x
⊢ Set.ncard sᶜ ≤ Set.ncard B
Tactic:
exact Set.ncard_le_ncard hsc_le_B
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
⊢ IsPretransitive (↥G) α
Tactic:
have hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G :=
  le_trans (le_of_lt hG) inf_le_left
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
⊢ IsPretransitive (↥G) α

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
⊢ IsPretransitive (↥G) α
Tactic:
apply Equiv.Perm.IsPretransitive.of_partition G s
State after:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
⊢ ∀ a ∈ s, ∀ b ∈ s, ∃ g, g • a = b

case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
⊢ ∀ a ∈ sᶜ, ∀ b ∈ sᶜ, ∃ g, g • a = b

case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
⊢ stabilizer (↥G) s ≠ ⊤

State before:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
⊢ ∀ a ∈ s, ∀ b ∈ s, ∃ g, g • a = b
Tactic:
intro a ha b hb
State after:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ s
b : α
hb : b ∈ s
⊢ ∃ g, g • a = b

State before:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ s
b : α
hb : b ∈ s
⊢ ∃ g, g • a = b
Tactic:
obtain ⟨g, hg, H⟩ := moves_in h4 s a ha b hb
State after:
case a.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ s
b : α
hb : b ∈ s
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α
H : g • a = b
⊢ ∃ g, g • a = b

State before:
case a.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ s
b : α
hb : b ∈ s
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α
H : g • a = b
⊢ ∃ g, g • a = b
Tactic:
use! g
State after:
case property
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ s
b : α
hb : b ∈ s
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α
H : g • a = b
⊢ g ∈ G

case h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ s
b : α
hb : b ∈ s
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α
H : g • a = b
⊢ { val := g, property := ?property } • a = b

State before:
case property
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ s
b : α
hb : b ∈ s
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α
H : g • a = b
⊢ g ∈ G

case h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ s
b : α
hb : b ∈ s
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α
H : g • a = b
⊢ { val := g, property := ?property } • a = b
Tactic:
exact hG' hg
State after:
case h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ s
b : α
hb : b ∈ s
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α
H : g • a = b
⊢ { val := g, property := ⋯ } • a = b

State before:
case h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ s
b : α
hb : b ∈ s
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α
H : g • a = b
⊢ { val := g, property := ⋯ } • a = b
Tactic:
exact H
State after:
no goals

State before:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
⊢ ∀ a ∈ sᶜ, ∀ b ∈ sᶜ, ∃ g, g • a = b
Tactic:
intro a ha b hb
State after:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
⊢ ∃ g, g • a = b

State before:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
⊢ ∃ g, g • a = b
Tactic:
obtain ⟨g, hg, H⟩ := moves_in h4 (sᶜ) a ha b hb
State after:
case a.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α
H : g • a = b
⊢ ∃ g, g • a = b

State before:
case a.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α
H : g • a = b
⊢ ∃ g, g • a = b
Tactic:
use! g
State after:
case property
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α
H : g • a = b
⊢ g ∈ G

case h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α
H : g • a = b
⊢ { val := g, property := ?property } • a = b

State before:
case property
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α
H : g • a = b
⊢ g ∈ G

case h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α
H : g • a = b
⊢ { val := g, property := ?property } • a = b
Tactic:
apply hG'
State after:
case property.a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α
H : g • a = b
⊢ g ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α

case h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α
H : g • a = b
⊢ { val := g, property := ⋯ } • a = b

State before:
case property.a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α
H : g • a = b
⊢ g ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α

case h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α
H : g • a = b
⊢ { val := g, property := ⋯ } • a = b
Tactic:
rw [stabilizer_compl] at hg
State after:
case property.a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α
H : g • a = b
⊢ g ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α

case h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α
H : g • a = b
⊢ { val := g, property := ⋯ } • a = b

State before:
case property.a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α
H : g • a = b
⊢ g ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α

case h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α
H : g • a = b
⊢ { val := g, property := ⋯ } • a = b
Tactic:
exact hg
State after:
case h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α
H : g • a = b
⊢ { val := g, property := ⋯ } • a = b

State before:
case h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
a : α
ha : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
g : Equiv.Perm α
hg : g ∈ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α
H : g • a = b
⊢ { val := g, property := ⋯ } • a = b
Tactic:
exact H
State after:
no goals

State before:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
⊢ stabilizer (↥G) s ≠ ⊤
Tactic:
intro h
State after:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
⊢ False

State before:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
⊢ False
Tactic:
apply (lt_iff_le_not_le.mp hG).right
State after:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
⊢ G ⊓ alternatingGroup α ≤ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α

State before:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
⊢ G ⊓ alternatingGroup α ≤ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α
Tactic:
rw [le_inf_iff]
State after:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
⊢ G ⊓ alternatingGroup α ≤ stabilizer (Equiv.Perm α) s ∧ G ⊓ alternatingGroup α ≤ alternatingGroup α

State before:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
⊢ G ⊓ alternatingGroup α ≤ stabilizer (Equiv.Perm α) s ∧ G ⊓ alternatingGroup α ≤ alternatingGroup α
Tactic:
constructor
State after:
case a.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
⊢ G ⊓ alternatingGroup α ≤ stabilizer (Equiv.Perm α) s

case a.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
⊢ G ⊓ alternatingGroup α ≤ alternatingGroup α

State before:
case a.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
⊢ G ⊓ alternatingGroup α ≤ stabilizer (Equiv.Perm α) s
Tactic:
intro g
State after:
case a.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
g : Equiv.Perm α
⊢ g ∈ G ⊓ alternatingGroup α → g ∈ stabilizer (Equiv.Perm α) s

State before:
case a.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
g : Equiv.Perm α
⊢ g ∈ G ⊓ alternatingGroup α → g ∈ stabilizer (Equiv.Perm α) s
Tactic:
rw [Subgroup.mem_inf, mem_stabilizer_iff]
State after:
case a.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
g : Equiv.Perm α
⊢ g ∈ G ∧ g ∈ alternatingGroup α → g • s = s

State before:
case a.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
g : Equiv.Perm α
⊢ g ∈ G ∧ g ∈ alternatingGroup α → g • s = s
Tactic:
rintro ⟨hg, _⟩
State after:
case a.left.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
g : Equiv.Perm α
hg : g ∈ G
right✝ : g ∈ alternatingGroup α
⊢ g • s = s

State before:
case a.left.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
g : Equiv.Perm α
hg : g ∈ G
right✝ : g ∈ alternatingGroup α
⊢ g • s = s
Tactic:
rw [← Subgroup.coe_mk G g hg]
State after:
case a.left.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
g : Equiv.Perm α
hg : g ∈ G
right✝ : g ∈ alternatingGroup α
⊢ ↑{ val := g, property := hg } • s = s

State before:
case a.left.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
g : Equiv.Perm α
hg : g ∈ G
right✝ : g ∈ alternatingGroup α
⊢ ↑{ val := g, property := hg } • s = s
Tactic:
change (⟨g, hg⟩ : ↥G) • s = s
State after:
case a.left.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
g : Equiv.Perm α
hg : g ∈ G
right✝ : g ∈ alternatingGroup α
⊢ { val := g, property := hg } • s = s

State before:
case a.left.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
g : Equiv.Perm α
hg : g ∈ G
right✝ : g ∈ alternatingGroup α
⊢ { val := g, property := hg } • s = s
Tactic:
rw [← mem_stabilizer_iff, h]
State after:
case a.left.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
g : Equiv.Perm α
hg : g ∈ G
right✝ : g ∈ alternatingGroup α
⊢ { val := g, property := hg } ∈ ⊤

State before:
case a.left.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
g : Equiv.Perm α
hg : g ∈ G
right✝ : g ∈ alternatingGroup α
⊢ { val := g, property := hg } ∈ ⊤
Tactic:
exact Subgroup.mem_top _
State after:
no goals

State before:
case a.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
hG' : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
h : stabilizer (↥G) s = ⊤
⊢ G ⊓ alternatingGroup α ≤ alternatingGroup α
Tactic:
exact inf_le_right
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
⊢ ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
Tactic:
intro B hB hBsc
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
⊢ False

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
⊢ False
Tactic:
obtain ⟨b, hb⟩ := h1.nonempty
State after:
case intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ sᶜ
⊢ False

State before:
case intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ sᶜ
⊢ False
Tactic:
rw [← hBsc] at hb
State after:
case intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
⊢ False

State before:
case intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
⊢ False
Tactic:
obtain ⟨a, ha⟩ := h0.nonempty
State after:
case intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
⊢ False

State before:
case intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
⊢ False
Tactic:
obtain ⟨k, hk⟩ := exists_smul_eq G b a
State after:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
⊢ False

State before:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
⊢ False
Tactic:
suffices Set.ncard (B : Set α) ≤ Set.ncard s by
  apply Nat.lt_irrefl (Set.ncard B)
  apply lt_of_le_of_lt this
  simp_rw [hBsc]; exact hα
State after:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
⊢ Set.ncard B ≤ Set.ncard s

State before:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
⊢ Set.ncard B ≤ Set.ncard s
Tactic:
rw [← smul_set_ncard_eq k B]
State after:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
⊢ Set.ncard (k • B) ≤ Set.ncard s

State before:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
⊢ Set.ncard (k • B) ≤ Set.ncard s
Tactic:
apply Set.ncard_le_ncard (ht := Set.toFinite s)
State after:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
⊢ k • B ⊆ s

State before:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
⊢ k • B ⊆ s
Tactic:
rw [← Set.disjoint_compl_right_iff_subset, ← hBsc]
State after:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
⊢ Disjoint (k • B) B

State before:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
⊢ Disjoint (k • B) B
Tactic:
apply or_iff_not_imp_left.mp (IsBlock.def_one.mp hB k)
State after:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
⊢ ¬k • B = B

State before:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
⊢ ¬k • B = B
Tactic:
intro h
State after:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
h : k • B = B
⊢ False

State before:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
h : k • B = B
⊢ False
Tactic:
apply Set.not_mem_empty a
State after:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
h : k • B = B
⊢ a ∈ ∅

State before:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
h : k • B = B
⊢ a ∈ ∅
Tactic:
rw [← Set.inter_compl_self s]
State after:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
h : k • B = B
⊢ a ∈ s ∩ sᶜ

State before:
case intro.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
h : k • B = B
⊢ a ∈ s ∩ sᶜ
Tactic:
constructor
State after:
case intro.intro.intro.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
h : k • B = B
⊢ a ∈ s

case intro.intro.intro.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
h : k • B = B
⊢ a ∈ sᶜ

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
this : Set.ncard B ≤ Set.ncard s
⊢ False
Tactic:
apply Nat.lt_irrefl (Set.ncard B)
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
this : Set.ncard B ≤ Set.ncard s
⊢ Set.ncard B < Set.ncard B

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
this : Set.ncard B ≤ Set.ncard s
⊢ Set.ncard B < Set.ncard B
Tactic:
apply lt_of_le_of_lt this
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
this : Set.ncard B ≤ Set.ncard s
⊢ Set.ncard s < Set.ncard B

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
this : Set.ncard B ≤ Set.ncard s
⊢ Set.ncard s < Set.ncard B
Tactic:
simp_rw [hBsc]
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
this : Set.ncard B ≤ Set.ncard s
⊢ Set.ncard s < Set.ncard sᶜ

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
this : Set.ncard B ≤ Set.ncard s
⊢ Set.ncard s < Set.ncard sᶜ
Tactic:
exact hα
State after:
no goals

State before:
case intro.intro.intro.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
h : k • B = B
⊢ a ∈ s
Tactic:
exact ha
State after:
no goals

State before:
case intro.intro.intro.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
h : k • B = B
⊢ a ∈ sᶜ
Tactic:
rw [← hk, ← hBsc, ← h, Set.smul_mem_smul_set_iff]
State after:
case intro.intro.intro.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
h : k • B = B
⊢ b ∈ B

State before:
case intro.intro.intro.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hBsc : B = sᶜ
b : α
hb : b ∈ B
a : α
ha : a ∈ s
k : ↥G
hk : k • b = a
h : k • B = B
⊢ b ∈ B
Tactic:
exact hb
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
⊢ ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
Tactic:
intro B hB hBsc
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ Set.Subsingleton B

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ Set.Subsingleton B
Tactic:
rw [← Equiv.Perm.Subtype.image_preimage_of_val hBsc]
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ Set.Subsingleton (Subtype.val '' (Subtype.val ⁻¹' B))

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ Set.Subsingleton (Subtype.val '' (Subtype.val ⁻¹' B))
Tactic:
apply Set.Subsingleton.image
State after:
case hs
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ Set.Subsingleton (Subtype.val ⁻¹' B)

State before:
case hs
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ Set.Subsingleton (Subtype.val ⁻¹' B)
Tactic:
suffices IsTrivialBlock (Subtype.val ⁻¹' B : Set (sᶜ : Set α)) by
  apply Or.resolve_right this
  intro hB'
  apply hB_ne_sc B hB
  simp only [Set.top_eq_univ, Set.preimage_eq_univ_iff, Subtype.range_coe_subtype] at hB'
  apply Set.Subset.antisymm hBsc hB'
State after:
case hs
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ IsTrivialBlock (Subtype.val ⁻¹' B)

State before:
case hs
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ IsTrivialBlock (Subtype.val ⁻¹' B)
Tactic:
suffices IsPreprimitive (stabilizer G (sᶜ : Set α)) (sᶜ : Set α) by
  refine' IsPreprimitive.has_trivial_blocks this _
  let φ' : stabilizer G (sᶜ : Set α) → G := Subtype.val
  let f' : (sᶜ : Set α) →ₑ[φ'] α := {
    toFun := Subtype.val
    map_smul' := fun m x => by simp only [SMul.smul_stabilizer_def] }
  apply MulAction.IsBlock_preimage f' hB
State after:
case hs
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ IsPreprimitive ↥(stabilizer (↥G) sᶜ) ↑sᶜ

State before:
case hs
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ IsPreprimitive ↥(stabilizer (↥G) sᶜ) ↑sᶜ
Tactic:
apply stabilizer.isPreprimitive'
State after:
case hs.hsc
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ Set.Nontrivial sᶜᶜ

case hs.hG
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α ≤ G

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsTrivialBlock (Subtype.val ⁻¹' B)
⊢ Set.Subsingleton (Subtype.val ⁻¹' B)
Tactic:
apply Or.resolve_right this
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsTrivialBlock (Subtype.val ⁻¹' B)
⊢ ¬Subtype.val ⁻¹' B = ⊤

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsTrivialBlock (Subtype.val ⁻¹' B)
⊢ ¬Subtype.val ⁻¹' B = ⊤
Tactic:
intro hB'
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsTrivialBlock (Subtype.val ⁻¹' B)
hB' : Subtype.val ⁻¹' B = ⊤
⊢ False

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsTrivialBlock (Subtype.val ⁻¹' B)
hB' : Subtype.val ⁻¹' B = ⊤
⊢ False
Tactic:
apply hB_ne_sc B hB
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsTrivialBlock (Subtype.val ⁻¹' B)
hB' : Subtype.val ⁻¹' B = ⊤
⊢ B = sᶜ

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsTrivialBlock (Subtype.val ⁻¹' B)
hB' : Subtype.val ⁻¹' B = ⊤
⊢ B = sᶜ
Tactic:
simp only [Set.top_eq_univ, Set.preimage_eq_univ_iff, Subtype.range_coe_subtype] at hB'
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsTrivialBlock (Subtype.val ⁻¹' B)
hB' : {x | x ∈ sᶜ} ⊆ B
⊢ B = sᶜ

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsTrivialBlock (Subtype.val ⁻¹' B)
hB' : {x | x ∈ sᶜ} ⊆ B
⊢ B = sᶜ
Tactic:
apply Set.Subset.antisymm hBsc hB'
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsPreprimitive ↥(stabilizer (↥G) sᶜ) ↑sᶜ
⊢ IsTrivialBlock (Subtype.val ⁻¹' B)
Tactic:
refine' IsPreprimitive.has_trivial_blocks this _
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsPreprimitive ↥(stabilizer (↥G) sᶜ) ↑sᶜ
⊢ IsBlock (↥(stabilizer (↥G) sᶜ)) (Subtype.val ⁻¹' B)

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsPreprimitive ↥(stabilizer (↥G) sᶜ) ↑sᶜ
⊢ IsBlock (↥(stabilizer (↥G) sᶜ)) (Subtype.val ⁻¹' B)
Tactic:
let φ' : stabilizer G (sᶜ : Set α) → G := Subtype.val
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsPreprimitive ↥(stabilizer (↥G) sᶜ) ↑sᶜ
φ' : ↥(stabilizer (↥G) sᶜ) → ↥G := Subtype.val
⊢ IsBlock (↥(stabilizer (↥G) sᶜ)) (Subtype.val ⁻¹' B)

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsPreprimitive ↥(stabilizer (↥G) sᶜ) ↑sᶜ
φ' : ↥(stabilizer (↥G) sᶜ) → ↥G := Subtype.val
⊢ IsBlock (↥(stabilizer (↥G) sᶜ)) (Subtype.val ⁻¹' B)
Tactic:
let f' : (sᶜ : Set α) →ₑ[φ'] α := {
  toFun := Subtype.val
  map_smul' := fun m x => by simp only [SMul.smul_stabilizer_def] }
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsPreprimitive ↥(stabilizer (↥G) sᶜ) ↑sᶜ
φ' : ↥(stabilizer (↥G) sᶜ) → ↥G := Subtype.val
f' : ↑sᶜ →ₑ[φ'] α := { toFun := Subtype.val, map_smul' := ⋯ }
⊢ IsBlock (↥(stabilizer (↥G) sᶜ)) (Subtype.val ⁻¹' B)

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsPreprimitive ↥(stabilizer (↥G) sᶜ) ↑sᶜ
φ' : ↥(stabilizer (↥G) sᶜ) → ↥G := Subtype.val
f' : ↑sᶜ →ₑ[φ'] α := { toFun := Subtype.val, map_smul' := ⋯ }
⊢ IsBlock (↥(stabilizer (↥G) sᶜ)) (Subtype.val ⁻¹' B)
Tactic:
apply MulAction.IsBlock_preimage f' hB
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
this : IsPreprimitive ↥(stabilizer (↥G) sᶜ) ↑sᶜ
φ' : ↥(stabilizer (↥G) sᶜ) → ↥G := Subtype.val
m : ↥(stabilizer (↥G) sᶜ)
x : ↑sᶜ
⊢ ↑(m • x) = φ' m • ↑x
Tactic:
simp only [SMul.smul_stabilizer_def]
State after:
no goals

State before:
case hs.hsc
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ Set.Nontrivial sᶜᶜ
Tactic:
rw [compl_compl]
State after:
case hs.hsc
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ Set.Nontrivial s

State before:
case hs.hsc
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ Set.Nontrivial s
Tactic:
exact h0
State after:
no goals

State before:
case hs.hG
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ stabilizer (Equiv.Perm α) sᶜ ⊓ alternatingGroup α ≤ G
Tactic:
rw [stabilizer_compl]
State after:
case hs.hG
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G

State before:
case hs.hG
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
B : Set α
hB : IsBlock (↥G) B
hBsc : B ⊆ sᶜ
⊢ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
Tactic:
exact le_trans (le_of_lt hG) inf_le_left
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
⊢ ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
Tactic:
intro B hB hBs
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
⊢ Set.Subsingleton B

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
⊢ IsTrivialBlock (Subtype.val ⁻¹' B)
Tactic:
suffices IsPreprimitive (stabilizer G s) (s : Set α) by
  refine' IsPreprimitive.has_trivial_blocks this _
  let φ' : stabilizer G s → G := Subtype.val
  let f' : s →ₑ[φ'] α := {
    toFun := Subtype.val
    map_smul' := fun ⟨m, _⟩ x => by simp }
  apply MulAction.IsBlock_preimage f' hB
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
⊢ IsPreprimitive ↥(stabilizer (↥G) s) ↑s

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
⊢ IsPreprimitive ↥(stabilizer (↥G) s) ↑s
Tactic:
apply stabilizer.isPreprimitive' s h1
State after:
case hG
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
⊢ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G

State before:
case hG
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
⊢ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α ≤ G
Tactic:
apply le_trans (le_of_lt hG) inf_le_left
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
this : IsTrivialBlock (Subtype.val ⁻¹' B)
⊢ Set.Subsingleton B
Tactic:
cases' this with hB' hB'
State after:
case inl
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Set.Subsingleton (Subtype.val ⁻¹' B)
⊢ Set.Subsingleton B

case inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
⊢ Set.Subsingleton B

State before:
case inl
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Set.Subsingleton (Subtype.val ⁻¹' B)
⊢ Set.Subsingleton B
Tactic:
rw [← Equiv.Perm.Subtype.image_preimage_of_val hBs]
State after:
case inl
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Set.Subsingleton (Subtype.val ⁻¹' B)
⊢ Set.Subsingleton (Subtype.val '' (Subtype.val ⁻¹' B))

State before:
case inl
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Set.Subsingleton (Subtype.val ⁻¹' B)
⊢ Set.Subsingleton (Subtype.val '' (Subtype.val ⁻¹' B))
Tactic:
apply Set.Subsingleton.image
State after:
case inl.hs
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Set.Subsingleton (Subtype.val ⁻¹' B)
⊢ Set.Subsingleton (Subtype.val ⁻¹' B)

State before:
case inl.hs
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Set.Subsingleton (Subtype.val ⁻¹' B)
⊢ Set.Subsingleton (Subtype.val ⁻¹' B)
Tactic:
exact hB'
State after:
no goals

State before:
case inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
⊢ Set.Subsingleton B
Tactic:
have hBs' : B = s := by
  apply Set.Subset.antisymm hBs
  intro x hx
  suffices x = Subtype.val (⟨x, hx⟩ : s) by
    rw [this, ← Set.mem_preimage, hB', Set.top_eq_univ]
    apply Set.mem_univ
  rfl
State after:
case inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
⊢ Set.Subsingleton B

State before:
case inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
⊢ Set.Subsingleton B
Tactic:
have : ∃ g' ∈ G, g' • s ≠ s := by
  by_contra h
  push_neg at h
  apply ne_of_lt hG
  apply le_antisymm (le_of_lt hG)
  intro g' hg'
  rw [Subgroup.mem_inf] at hg' ⊢
  exact ⟨h g' hg'.left, hg'.right⟩
State after:
case inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
this : ∃ g' ∈ G, g' • s ≠ s
⊢ Set.Subsingleton B

State before:
case inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
this : ∃ g' ∈ G, g' • s ≠ s
⊢ Set.Subsingleton B
Tactic:
obtain ⟨g', hg', hg's⟩ := this
State after:
case inr.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
⊢ Set.Subsingleton B

State before:
case inr.intro.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
⊢ Set.Subsingleton B
Tactic:
cases' IsBlock.def_one.mp hB ⟨g', hg'⟩ with h h
State after:
case inr.intro.intro.inl
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : { val := g', property := hg' } • B = B
⊢ Set.Subsingleton B

case inr.intro.intro.inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : Disjoint ({ val := g', property := hg' } • B) B
⊢ Set.Subsingleton B

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
⊢ B = s
Tactic:
apply Set.Subset.antisymm hBs
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
⊢ s ⊆ B

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
⊢ s ⊆ B
Tactic:
intro x hx
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
x : α
hx : x ∈ s
⊢ x ∈ B

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
x : α
hx : x ∈ s
⊢ x ∈ B
Tactic:
suffices x = Subtype.val (⟨x, hx⟩ : s) by
  rw [this, ← Set.mem_preimage, hB', Set.top_eq_univ]
  apply Set.mem_univ
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
x : α
hx : x ∈ s
⊢ x = ↑{ val := x, property := hx }

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
x : α
hx : x ∈ s
⊢ x = ↑{ val := x, property := hx }
Tactic:
rfl
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
x : α
hx : x ∈ s
this : x = ↑{ val := x, property := hx }
⊢ x ∈ B
Tactic:
rw [this, ← Set.mem_preimage, hB', Set.top_eq_univ]
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
x : α
hx : x ∈ s
this : x = ↑{ val := x, property := hx }
⊢ { val := x, property := hx } ∈ Set.univ

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
x : α
hx : x ∈ s
this : x = ↑{ val := x, property := hx }
⊢ { val := x, property := hx } ∈ Set.univ
Tactic:
apply Set.mem_univ
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
⊢ ∃ g' ∈ G, g' • s ≠ s
Tactic:
by_contra h
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
h : ¬∃ g' ∈ G, g' • s ≠ s
⊢ False

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
h : ¬∃ g' ∈ G, g' • s ≠ s
⊢ False
Tactic:
push_neg at h
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
h : ∀ g' ∈ G, g' • s = s
⊢ False

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
h : ∀ g' ∈ G, g' • s = s
⊢ False
Tactic:
apply ne_of_lt hG
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
h : ∀ g' ∈ G, g' • s = s
⊢ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α = G ⊓ alternatingGroup α

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
h : ∀ g' ∈ G, g' • s = s
⊢ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α = G ⊓ alternatingGroup α
Tactic:
apply le_antisymm (le_of_lt hG)
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
h : ∀ g' ∈ G, g' • s = s
⊢ G ⊓ alternatingGroup α ≤ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
h : ∀ g' ∈ G, g' • s = s
⊢ G ⊓ alternatingGroup α ≤ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α
Tactic:
intro g' hg'
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
h : ∀ g' ∈ G, g' • s = s
g' : Equiv.Perm α
hg' : g' ∈ G ⊓ alternatingGroup α
⊢ g' ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
h : ∀ g' ∈ G, g' • s = s
g' : Equiv.Perm α
hg' : g' ∈ G ⊓ alternatingGroup α
⊢ g' ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α
Tactic:
rw [Subgroup.mem_inf] at hg' ⊢
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
h : ∀ g' ∈ G, g' • s = s
g' : Equiv.Perm α
hg' : g' ∈ G ∧ g' ∈ alternatingGroup α
⊢ g' ∈ stabilizer (Equiv.Perm α) s ∧ g' ∈ alternatingGroup α

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
h : ∀ g' ∈ G, g' • s = s
g' : Equiv.Perm α
hg' : g' ∈ G ∧ g' ∈ alternatingGroup α
⊢ g' ∈ stabilizer (Equiv.Perm α) s ∧ g' ∈ alternatingGroup α
Tactic:
exact ⟨h g' hg'.left, hg'.right⟩
State after:
no goals

State before:
case inr.intro.intro.inl
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : { val := g', property := hg' } • B = B
⊢ Set.Subsingleton B
Tactic:
exfalso
State after:
case inr.intro.intro.inl
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : { val := g', property := hg' } • B = B
⊢ False

State before:
case inr.intro.intro.inl
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : { val := g', property := hg' } • B = B
⊢ False
Tactic:
apply hg's
State after:
case inr.intro.intro.inl
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : { val := g', property := hg' } • B = B
⊢ g' • s = s

State before:
case inr.intro.intro.inl
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : { val := g', property := hg' } • B = B
⊢ g' • s = s
Tactic:
rw [← hBs']
State after:
case inr.intro.intro.inl
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : { val := g', property := hg' } • B = B
⊢ g' • B = B

State before:
case inr.intro.intro.inl
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : { val := g', property := hg' } • B = B
⊢ g' • B = B
Tactic:
exact h
State after:
no goals

State before:
case inr.intro.intro.inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : Disjoint ({ val := g', property := hg' } • B) B
⊢ Set.Subsingleton B
Tactic:
suffices (g' • B).Subsingleton by
  apply Set.subsingleton_of_image _ B this
  apply Function.Bijective.injective (MulAction.bijective _)
State after:
case inr.intro.intro.inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : Disjoint ({ val := g', property := hg' } • B) B
⊢ Set.Subsingleton (g' • B)

State before:
case inr.intro.intro.inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : Disjoint ({ val := g', property := hg' } • B) B
⊢ Set.Subsingleton (g' • B)
Tactic:
apply hB_not_le_sc ((⟨g', hg'⟩ : G) • B) (IsBlock_of_block _ hB)
State after:
case inr.intro.intro.inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : Disjoint ({ val := g', property := hg' } • B) B
⊢ { val := g', property := hg' } • B ⊆ sᶜ

State before:
case inr.intro.intro.inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : Disjoint ({ val := g', property := hg' } • B) B
⊢ { val := g', property := hg' } • B ⊆ sᶜ
Tactic:
rw [← hBs']
State after:
case inr.intro.intro.inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : Disjoint ({ val := g', property := hg' } • B) B
⊢ { val := g', property := hg' } • B ⊆ Bᶜ

State before:
case inr.intro.intro.inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : Disjoint ({ val := g', property := hg' } • B) B
⊢ { val := g', property := hg' } • B ⊆ Bᶜ
Tactic:
exact Disjoint.subset_compl_right h
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : Disjoint ({ val := g', property := hg' } • B) B
this : Set.Subsingleton (g' • B)
⊢ Set.Subsingleton B
Tactic:
apply Set.subsingleton_of_image _ B this
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : Disjoint ({ val := g', property := hg' } • B) B
this : Set.Subsingleton (g' • B)
⊢ Function.Injective fun x => g' • x

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
hB' : Subtype.val ⁻¹' B = ⊤
hBs' : B = s
g' : Equiv.Perm α
hg' : g' ∈ G
hg's : g' • s ≠ s
h : Disjoint ({ val := g', property := hg' } • B) B
this : Set.Subsingleton (g' • B)
⊢ Function.Injective fun x => g' • x
Tactic:
apply Function.Bijective.injective (MulAction.bijective _)
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
this : IsPreprimitive ↥(stabilizer (↥G) s) ↑s
⊢ IsTrivialBlock (Subtype.val ⁻¹' B)
Tactic:
refine' IsPreprimitive.has_trivial_blocks this _
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
this : IsPreprimitive ↥(stabilizer (↥G) s) ↑s
⊢ IsBlock (↥(stabilizer (↥G) s)) (Subtype.val ⁻¹' B)

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
this : IsPreprimitive ↥(stabilizer (↥G) s) ↑s
⊢ IsBlock (↥(stabilizer (↥G) s)) (Subtype.val ⁻¹' B)
Tactic:
let φ' : stabilizer G s → G := Subtype.val
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
this : IsPreprimitive ↥(stabilizer (↥G) s) ↑s
φ' : ↥(stabilizer (↥G) s) → ↥G := Subtype.val
⊢ IsBlock (↥(stabilizer (↥G) s)) (Subtype.val ⁻¹' B)

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
this : IsPreprimitive ↥(stabilizer (↥G) s) ↑s
φ' : ↥(stabilizer (↥G) s) → ↥G := Subtype.val
⊢ IsBlock (↥(stabilizer (↥G) s)) (Subtype.val ⁻¹' B)
Tactic:
let f' : s →ₑ[φ'] α := {
  toFun := Subtype.val
  map_smul' := fun ⟨m, _⟩ x => by simp }
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
this : IsPreprimitive ↥(stabilizer (↥G) s) ↑s
φ' : ↥(stabilizer (↥G) s) → ↥G := Subtype.val
f' : ↑s →ₑ[φ'] α := { toFun := Subtype.val, map_smul' := ⋯ }
⊢ IsBlock (↥(stabilizer (↥G) s)) (Subtype.val ⁻¹' B)

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
this : IsPreprimitive ↥(stabilizer (↥G) s) ↑s
φ' : ↥(stabilizer (↥G) s) → ↥G := Subtype.val
f' : ↑s →ₑ[φ'] α := { toFun := Subtype.val, map_smul' := ⋯ }
⊢ IsBlock (↥(stabilizer (↥G) s)) (Subtype.val ⁻¹' B)
Tactic:
apply MulAction.IsBlock_preimage f' hB
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hBs : B ⊆ s
this : IsPreprimitive ↥(stabilizer (↥G) s) ↑s
φ' : ↥(stabilizer (↥G) s) → ↥G := Subtype.val
x✝ : ↥(stabilizer (↥G) s)
x : ↑s
m : ↥G
property✝ : m ∈ stabilizer (↥G) s
⊢ ↑({ val := m, property := property✝ } • x) = φ' { val := m, property := property✝ } • ↑x
Tactic:
simp
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
⊢ sᶜ ⊆ B
Tactic:
intro x hx'
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
⊢ x ∈ B

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
this : ∃ k, k • b = x
⊢ x ∈ B
Tactic:
obtain ⟨⟨k, hk⟩, hkbx : k • b = x⟩ := this
State after:
case intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ x ∈ B

State before:
case intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ x ∈ B
Tactic:
suffices k • B = B by
  rw [← hkbx, ← this, Set.smul_mem_smul_set_iff]
  exact hb
State after:
case intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ k • B = B

State before:
case intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ k • B = B
Tactic:
apply or_iff_not_imp_right.mp (IsBlock.def_one.mp hB ⟨k, _⟩)
State after:
case intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ¬Disjoint ({ val := ↑k, property := ?m.99446 } • B) B

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G

State before:
case intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ¬Disjoint ({ val := ↑k, property := ?m.99446 } • B) B

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G
Tactic:
rw [Set.not_disjoint_iff_nonempty_inter]
State after:
case intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ Set.Nonempty ({ val := ↑k, property := ?m.99446 } • B ∩ B)

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G

State before:
case intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ Set.Nonempty ({ val := ↑k, property := ?m.99446 } • B ∩ B)

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G
Tactic:
change (k • B ∩ B).Nonempty
State after:
case intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ Set.Nonempty (k • B ∩ B)

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G

State before:
case intro.mk
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ Set.Nonempty (k • B ∩ B)

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G
Tactic:
use a
State after:
case h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ a ∈ k • B ∩ B

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G

State before:
case h
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ a ∈ k • B ∩ B

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G
Tactic:
constructor
State after:
case h.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ a ∈ k • B

case h.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ a ∈ B

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G

α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
this : k • B = B
⊢ x ∈ B
Tactic:
rw [← hkbx, ← this, Set.smul_mem_smul_set_iff]
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
this : k • B = B
⊢ b ∈ B

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
this : k • B = B
⊢ b ∈ B
Tactic:
exact hb
State after:
no goals

State before:
case h.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ a ∈ k • B
Tactic:
rw [mem_fixingSubgroup_iff] at hk
State after:
case h.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : ∀ y ∈ s, k • y = y
hkbx : k • b = x
⊢ a ∈ k • B

State before:
case h.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : ∀ y ∈ s, k • y = y
hkbx : k • b = x
⊢ a ∈ k • B
Tactic:
rw [← hk a ha']
State after:
case h.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : ∀ y ∈ s, k • y = y
hkbx : k • b = x
⊢ k • a ∈ k • B

State before:
case h.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : ∀ y ∈ s, k • y = y
hkbx : k • b = x
⊢ k • a ∈ k • B
Tactic:
exact Set.smul_mem_smul_set ha
State after:
no goals

State before:
case h.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ a ∈ B
Tactic:
exact ha
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ G
Tactic:
apply le_trans (le_of_lt hG)
State after:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ G ⊓ alternatingGroup α ≤ G

case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α

State before:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ G ⊓ alternatingGroup α ≤ G

case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α
Tactic:
exact inf_le_left
State after:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α

State before:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α
Tactic:
rw [Subgroup.mem_inf]
State after:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ stabilizer (Equiv.Perm α) s ∧ ↑k ∈ alternatingGroup α

State before:
case a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ stabilizer (Equiv.Perm α) s ∧ ↑k ∈ alternatingGroup α
Tactic:
constructor
State after:
case a.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ stabilizer (Equiv.Perm α) s

case a.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ alternatingGroup α

State before:
case a.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ stabilizer (Equiv.Perm α) s

case a.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ alternatingGroup α
Tactic:
suffices hk' : k ∈ stabilizer (alternatingGroup α) s by
  simpa [mem_stabilizer_iff] using hk'
State after:
case a.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ k ∈ stabilizer (↥(alternatingGroup α)) s

case a.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ alternatingGroup α

State before:
case a.left
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ k ∈ stabilizer (↥(alternatingGroup α)) s

case a.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ alternatingGroup α
Tactic:
apply MulAction.fixingSubgroup_le_stabilizer
State after:
case a.left.a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ k ∈ fixingSubgroup (↥(alternatingGroup α)) s

case a.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ alternatingGroup α

State before:
case a.left.a
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ k ∈ fixingSubgroup (↥(alternatingGroup α)) s

case a.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ alternatingGroup α
Tactic:
exact hk
State after:
case a.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ alternatingGroup α

State before:
case a.right
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
⊢ ↑k ∈ alternatingGroup α
Tactic:
exact k.prop
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
k : ↥(alternatingGroup α)
hk : k ∈ fixingSubgroup (↥(alternatingGroup α)) s
hkbx : k • b = x
hk' : k ∈ stabilizer (↥(alternatingGroup α)) s
⊢ ↑k ∈ stabilizer (Equiv.Perm α) s
Tactic:
simpa [mem_stabilizer_iff] using hk'
State after:
no goals

State before:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
⊢ ∃ k, k • b = x
Tactic:
haveI : IsPretransitive (fixingSubgroup (alternatingGroup α) s)
    (SubMulAction.ofFixingSubgroup (alternatingGroup α) s) :=
  isPretransitive_ofFixingSubgroup s h0 hα
State after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
s : Set α
h0 : Set.Nontrivial s
h1 : Set.Nontrivial sᶜ
hα : Set.ncard s < Set.ncard sᶜ
h4 : 4 ≤ Fintype.card α
G : Subgroup (Equiv.Perm α)
hG : stabilizer (Equiv.Perm α) s ⊓ alternatingGroup α < G ⊓ alternatingGroup α
this✝ : IsPretransitive (↥G) α
hB_ne_sc : ∀ (B : Set α), IsBlock (↥G) B → ¬B = sᶜ
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → Set.Subsingleton B
hB_not_le_s : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ s → Set.Subsingleton B
B : Set α
hB : IsBlock (↥G) B
hB' : ¬Set.Subsingleton B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
x : α
hx' : x ∈ sᶜ
this :
  IsPretransitive ↥(fixingSubgroup (↥(alternatingGroup α)) s) ↥(SubMulAction.ofFixingSubgroup (↥(alternatingGroup α)) s)
⊢ ∃ k, k • b = x