-- Mathlib/GroupTheory/GroupAction/Primitive.lean
theorem isSimpleOrder_blockMem_iff_isPreprimitive [IsPretransitive G X] [Nontrivial X] (a : X) :
    IsSimpleOrder (BlockMem G a) ↔ IsPreprimitive G X

Proof state:
case mpr.eq_bot_or_eq_top.mk.intro.inr
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
hGX' : IsPreprimitive G X
B : Set X
haB : a ∈ B
hB : IsBlock G B
h : B = Set.univ
⊢ B = ↑⊥ ∨ B = ↑⊤

Tactic:
simp [BlockMem.coe_top, h]

Result:
no goals

Proof state:
case mp.inl
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
h : IsSimpleOrder (BlockMem G a)
h_bot_or_top : ∀ (a_1 : BlockMem G a), a_1 = ⊥ ∨ a_1 = ⊤ := eq_bot_or_eq_top
B : Set X
haB : a ∈ B
hB : IsBlock G B
hB' : B = ↑⊥
⊢ IsTrivialBlock B

Tactic:
left

Result:
case mp.inl.h
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
h : IsSimpleOrder (BlockMem G a)
h_bot_or_top : ∀ (a_1 : BlockMem G a), a_1 = ⊥ ∨ a_1 = ⊤ := eq_bot_or_eq_top
B : Set X
haB : a ∈ B
hB : IsBlock G B
hB' : B = ↑⊥
⊢ B.Subsingleton

Proof state:
case mpr.eq_bot_or_eq_top.mk.intro.inl
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
hGX' : IsPreprimitive G X
B : Set X
haB : a ∈ B
hB : IsBlock G B
h : B.Subsingleton
⊢ B = ↑⊥ ∨ B = ↑⊤

Tactic:
simp [BlockMem.coe_bot, h.eq_singleton_of_mem haB]

Result:
no goals

Proof state:
case mp.inl.h
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
h : IsSimpleOrder (BlockMem G a)
h_bot_or_top : ∀ (a_1 : BlockMem G a), a_1 = ⊥ ∨ a_1 = ⊤ := eq_bot_or_eq_top
B : Set X
haB : a ∈ B
hB : IsBlock G B
hB' : B = ↑⊥
⊢ B.Subsingleton

Tactic:
rw [hB']

Result:
case mp.inl.h
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
h : IsSimpleOrder (BlockMem G a)
h_bot_or_top : ∀ (a_1 : BlockMem G a), a_1 = ⊥ ∨ a_1 = ⊤ := eq_bot_or_eq_top
B : Set X
haB : a ∈ B
hB : IsBlock G B
hB' : B = ↑⊥
⊢ (↑⊥).Subsingleton

Proof state:
case mp.inr
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
h : IsSimpleOrder (BlockMem G a)
h_bot_or_top : ∀ (a_1 : BlockMem G a), a_1 = ⊥ ∨ a_1 = ⊤ := eq_bot_or_eq_top
B : Set X
haB : a ∈ B
hB : IsBlock G B
hB' : B = ↑⊤
⊢ IsTrivialBlock B

Tactic:
right

Result:
case mp.inr.h
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
h : IsSimpleOrder (BlockMem G a)
h_bot_or_top : ∀ (a_1 : BlockMem G a), a_1 = ⊥ ∨ a_1 = ⊤ := eq_bot_or_eq_top
B : Set X
haB : a ∈ B
hB : IsBlock G B
hB' : B = ↑⊤
⊢ B = Set.univ

Proof state:
case mpr.eq_bot_or_eq_top.mk.intro
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
hGX' : IsPreprimitive G X
B : Set X
haB : a ∈ B
hB : IsBlock G B
⊢ B = ↑⊥ ∨ B = ↑⊤

Tactic:
cases hGX'.isTrivialBlock_of_isBlock hB with
| inl h =>
  simp [BlockMem.coe_bot, h.eq_singleton_of_mem haB]
| inr h =>
  simp [BlockMem.coe_top, h]

Result:
no goals

Proof state:
case mp
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
h : IsSimpleOrder (BlockMem G a)
⊢ IsPreprimitive G X

Tactic:
let h_bot_or_top := h.eq_bot_or_eq_top

Result:
case mp
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
h : IsSimpleOrder (BlockMem G a)
h_bot_or_top : ∀ (a_1 : BlockMem G a), a_1 = ⊥ ∨ a_1 = ⊤ := eq_bot_or_eq_top
⊢ IsPreprimitive G X

Proof state:
case mp
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
h : IsSimpleOrder (BlockMem G a)
h_bot_or_top : ∀ (a_1 : BlockMem G a), a_1 = ⊥ ∨ a_1 = ⊤ := eq_bot_or_eq_top
B : Set X
haB : a ∈ B
hB : IsBlock G B
⊢ IsTrivialBlock B

Tactic:
rcases h_bot_or_top ⟨B, haB, hB⟩ with hB' | hB' <;>
  simp only [← Subtype.coe_inj, Subtype.coe_mk] at hB'

Result:
case mp.inl
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
h : IsSimpleOrder (BlockMem G a)
h_bot_or_top : ∀ (a_1 : BlockMem G a), a_1 = ⊥ ∨ a_1 = ⊤ := eq_bot_or_eq_top
B : Set X
haB : a ∈ B
hB : IsBlock G B
hB' : B = ↑⊥
⊢ IsTrivialBlock B

case mp.inr
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
h : IsSimpleOrder (BlockMem G a)
h_bot_or_top : ∀ (a_1 : BlockMem G a), a_1 = ⊥ ∨ a_1 = ⊤ := eq_bot_or_eq_top
B : Set X
haB : a ∈ B
hB : IsBlock G B
hB' : B = ↑⊤
⊢ IsTrivialBlock B

Proof state:
case mp
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
⊢ IsSimpleOrder (BlockMem G a) → IsPreprimitive G X

Tactic:
intro h

Result:
case mp
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
h : IsSimpleOrder (BlockMem G a)
⊢ IsPreprimitive G X

Proof state:
case mpr
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
⊢ IsPreprimitive G X → IsSimpleOrder (BlockMem G a)

Tactic:
intro hGX'

Result:
case mpr
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
hGX' : IsPreprimitive G X
⊢ IsSimpleOrder (BlockMem G a)

Proof state:
case mp
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
h : IsSimpleOrder (BlockMem G a)
h_bot_or_top : ∀ (a_1 : BlockMem G a), a_1 = ⊥ ∨ a_1 = ⊤ := eq_bot_or_eq_top
⊢ IsPreprimitive G X

Tactic:
apply IsPreprimitive.of_isTrivialBlock_base a

Result:
case mp
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
h : IsSimpleOrder (BlockMem G a)
h_bot_or_top : ∀ (a_1 : BlockMem G a), a_1 = ⊥ ∨ a_1 = ⊤ := eq_bot_or_eq_top
⊢ ∀ {B : Set X}, a ∈ B → IsBlock G B → IsTrivialBlock B

Proof state:
case mpr.eq_bot_or_eq_top.mk.intro
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
hGX' : IsPreprimitive G X
B : Set X
haB : a ∈ B
hB : IsBlock G B
⊢ ⟨B, ⋯⟩ = ⊥ ∨ ⟨B, ⋯⟩ = ⊤

Tactic:
simp only [← Subtype.coe_inj, Subtype.coe_mk]

Result:
case mpr.eq_bot_or_eq_top.mk.intro
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
hGX' : IsPreprimitive G X
B : Set X
haB : a ∈ B
hB : IsBlock G B
⊢ B = ↑⊥ ∨ B = ↑⊤

Proof state:
case mpr
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
hGX' : IsPreprimitive G X
⊢ IsSimpleOrder (BlockMem G a)

Tactic:
apply IsSimpleOrder.mk

Result:
case mpr.eq_bot_or_eq_top
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
hGX' : IsPreprimitive G X
⊢ ∀ (a_1 : BlockMem G a), a_1 = ⊥ ∨ a_1 = ⊤

Proof state:
case mp.inl.h
G : Type u_3
inst✝³ : Group G
X : Type u_4
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
inst✝ : Nontrivial X
a : X
h : IsSimpleOrder (BlockMem G a)
h_bot_or_top : ∀ (a_1 : BlockMem G a), a_1 = ⊥ ∨ a_1 = ⊤ := eq_bot_or_eq_top
B : Set X
haB : a ∈ B
hB : IsBlock G B
hB' : B = ↑⊥
⊢ (↑⊥).Subsingleton

Tactic:
exact Set.subsingleton_singleton

Result:
no goals