mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.GroupTheory.GroupAction.MultipleTransitivity

Goal state before:
pp: case inr.inr
α : Type u_1
inst✝ : Finite α
G : Subgroup (Perm α)
this : Fintype α
hmt : IsMultiplyPretransitive (↥G) α (Fintype.card α - 1)
j✝ : Fin (Fintype.card α - 1) ↪ Fin (Fintype.card α) := castLEEmb ⋯
k : Perm α
a✝ : k ∈ ⊤
x : Fin (Fintype.card α) ↪ α := (Fintype.equivFinOfCardEq ⋯).symm.toEmbedding
x' : Fin (Fintype.card α - 1) ↪ α := j✝.trans x
g : ↥G
hg' : g • x' = k • x'
hx : ∀ (x : Fin (Fintype.card α) ↪ α), Function.Surjective x.toFun
hgk' : ∀ (i : Fin (Fintype.card α)), ↑i < Fintype.card α - 1 → (g • x) i = (k • x) i
i : Fin (Fintype.card α)
hi : ↑i = Fintype.card α - 1
j : Fin (Fintype.card α)
hxj : (k • x) j = (g • x) i
hj : ↑j = Fintype.card α - 1
⊢ (k • x) j = (k • x) i

Tactic:
apply congr_arg

Goal state after:
case inr.inr
α : Type u_1
inst✝ : Finite α
G : Subgroup (Perm α)
this : Fintype α
hmt : IsMultiplyPretransitive (↥G) α (Fintype.card α - 1)
j✝ : Fin (Fintype.card α - 1) ↪ Fin (Fintype.card α) := ⋯
k : Perm α
a✝ : k ∈ ⊤
x : Fin (Fintype.card α) ↪ α := ⋯
x' : Fin (Fintype.card α - 1) ↪ α := ⋯
g : ↥G
hg' : g • x' = k • x'
hx : ∀ (x : Fin (Fintype.card α) ↪ α), Function.Surjective x.toFun
hgk' : ∀ (i : Fin (Fintype.card α)), ↑i < Fintype.card α - 1 → (g • x) i = (k • x) i
i : Fin (Fintype.card α)
hi : ↑i = Fintype.card α - 1
j : Fin (Fintype.card α)
hxj : (k • x) j = (g • x) i
hj : ↑j = Fintype.card α - 1
⊢ j = i
Module: Mathlib.GroupTheory.GroupAction.MultiplePrimitivity

Goal state before:
pp: M : Type u_1
α : Type u_2
inst✝³ : Group M
inst✝² : MulAction M α
N : Type u_3
β : Type u_4
inst✝¹ : Group N
inst✝ : MulAction N β
φ : M → N
f : α →ₑ[φ] β
hf : Function.Bijective ⇑f
n : ℕ
h : IsMultiplyPreprimitive M α n
t : Set β
ht : t.encard + 1 = ↑n
s : Set α := ⇑f ⁻¹' t
hs' : ⇑f '' s = t
x✝¹ : ↥(fixingSubgroup M s)
m : M
hm : m ∈ fixingSubgroup M s
x✝ : ↑t
y : β
hy : y ∈ t
x : α
hx : x ∈ s
hx' : f x = y
⊢ f (m • x) = f x

Tactic:
apply congr_arg

Goal state after:
M : Type u_1
α : Type u_2
inst✝³ : Group M
inst✝² : MulAction M α
N : Type u_3
β : Type u_4
inst✝¹ : Group N
inst✝ : MulAction N β
φ : M → N
f : α →ₑ[φ] β
hf : Function.Bijective ⇑f
n : ℕ
h : IsMultiplyPreprimitive M α n
t : Set β
ht : t.encard + 1 = ↑n
s : Set α := ⋯
hs' : ⇑f '' s = t
x✝¹ : ↥(fixingSubgroup M s)
m : M
hm : m ∈ fixingSubgroup M s
x✝ : ↑t
y : β
hy : y ∈ t
x : α
hx : x ∈ s
hx' : f x = y
⊢ m • x = x
Module: Mathlib.GroupTheory.GroupAction.SubMulAction.OfFixingSubgroup

Goal state before:
pp: case inr
M : Type u_1
α : Type u_2
inst✝¹ : Group M
inst✝ : MulAction M α
s : Set α
hs : IsPretransitive ↥(fixingSubgroup M s) ↥(ofFixingSubgroup M s)
g : M
a : α
ha : a ∈ sᶜ ∩ (g • s)ᶜ
ha' : a ∈ (s ∩ g • s)ᶜ
x : α
hx✝ : x ∈ ofFixingSubgroup M (s ∩ g • s)
hx : x ∉ g • s
⊢ ∃ g_1, g_1 • ⟨a, ha'⟩ = ⟨x, hx✝⟩

Tactic:
have hg'x : g⁻¹ • x ∈ ofFixingSubgroup M s := mt Set.mem_smul_set_iff_inv_smul_mem.mpr hx

Goal state after:
case inr
M : Type u_1
α : Type u_2
inst✝¹ : Group M
inst✝ : MulAction M α
s : Set α
hs : IsPretransitive ↥(fixingSubgroup M s) ↥(ofFixingSubgroup M s)
g : M
a : α
ha : a ∈ sᶜ ∩ (g • s)ᶜ
ha' : a ∈ (s ∩ g • s)ᶜ
x : α
hx✝ : x ∈ ofFixingSubgroup M (s ∩ g • s)
hx : x ∉ g • s
hg'x : g⁻¹ • x ∈ ofFixingSubgroup M s
⊢ ∃ g_1, g_1 • ⟨a, ha'⟩ = ⟨x, hx✝⟩
Module: Mathlib.GroupTheory.GroupAction.MultipleTransitivity

Goal state before:
pp: case inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
G : Subgroup (Equiv.Perm α)
hα : Nat.card α ≥ 2
s : Set α
hmt : IsMultiplyPretransitive (↥G) α s.ncard
left✝ : s ⊆ univ
hs : s.ncard = Nat.card α - 2
⊢ G.index ≤ 2

Tactic:
have := hmt.index_of_fixingSubgroup_mul rfl

Goal state after:
case inr
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
G : Subgroup (Equiv.Perm α)
hα : Nat.card α ≥ 2
s : Set α
hmt : IsMultiplyPretransitive (↥G) α s.ncard
left✝ : s ⊆ univ
hs : s.ncard = Nat.card α - 2
this : (fixingSubgroup (↥G) s).index * (Nat.card α - s.ncard)! = (Nat.card α)!
⊢ G.index ≤ 2
Module: Mathlib.GroupTheory.Perm.MaximalSubgroups

Goal state before:
pp: M : Type u_1
α : Type u_2
inst✝² : Group M
inst✝¹ : MulAction M α
s B : Set α
G : Subgroup M
inst✝ : IsPreprimitive ↥(stabilizer (↥G) s) ↑s
hB : IsBlock (↥G) B
hB_not_le_sc : ∀ (B : Set α), IsBlock (↥G) B → B ⊆ sᶜ → B.Subsingleton
hG : stabilizer M s < G
hBs : B ⊆ s
⊢ B.Subsingleton

Tactic:
suffices IsTrivialBlock (Subtype.val ⁻¹' B : Set s) by
    rcases this with hB' | hB'
    · -- trivial case
      rw [← inter_eq_self_of_subset_right hBs, ← Subtype.image_preimage_val]
      apply Set.Subsingleton.image hB'
    · -- `Subtype.val ⁻¹' B = s`
      have hBs' : B = s := Set.Subset.antisymm hBs (by simp_all)
      subst hBs'
      obtain ⟨g', hg', hg's⟩ := SetLike.exists_of_lt hG
      have h := (isBlock_iff_smul_eq_or_disjoint.mp hB ⟨g', hg'⟩).resolve_left hg's
      suffices (g' • B).Subsingleton by
        exact subsingleton_of_image (MulAction.injective g') B this
      apply hB_not_le_sc (⟨g', hg'⟩ • B) (hB.translate _)
      exact Disjoint.subset_compl_right h
  -- `IsTrivialBlock (Subtype.val ⁻¹' B : Set s)`
  suffices IsPreprimitive (stabilizer G s) s by
    apply this.isTrivialBlock_of_isBlock
    -- `IsBlock (Subtype.val ⁻¹' B : Set s)`
    let φ' : stabilizer G s → G := Subtype.val
    let f' : s →ₑ[φ'] α := {
      toFun := Subtype.val
      map_smul' _ _ := rfl }
    apply MulAction.IsBlock.preimage f' hB
  infer_instance

Goal state after:
Module: Mathlib.GroupTheory.Perm.MaximalSubgroups

Goal state before:
pp: α : Type u_2
inst✝ : Finite α
s : Set α
h0 : s.Nonempty
hα : s.ncard < sᶜ.ncard
h1 : sᶜ.Nonempty
this✝¹ : Fintype α
G : Subgroup (Perm α)
hG : stabilizer (Perm α) s < G
hG' : stabilizer (Perm α) sᶜ < G
g : Perm α
hg_swap : g.IsSwap
hg : g ∈ G
this✝ : IsPretransitive (↥G) α
B : Set α
hB : IsBlock (↥G) B
hB' : ¬B.Subsingleton
this : sᶜ ⊆ B
⊢ B = univ

Tactic:
apply hB.eq_univ_of_card_lt
    have : sᶜ.ncard ≤ B.ncard := ncard_le_ncard this
    rw [← Set.ncard_add_ncard_compl s]
    lia

Goal state after:
Module: Mathlib.GroupTheory.GroupAction.Jordan

Goal state before:
pp: case refine_2
n : ℕ
hrec :
  ∀ {G : Type u_1} {α : Type u_2} [inst : Group G] [inst_1 : MulAction G α],
    IsPreprimitive G α →
      ∀ {s : Set α},
        s.ncard = n + 1 →
          n + 2 < Nat.card α →
            IsPreprimitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → Finite α → IsMultiplyPreprimitive G α (n + 2)
G : Type u_1
α : Type u_2
inst✝¹ : Group G
inst✝ : MulAction G α
hG : IsPreprimitive G α
s : Set α
hsn : s.ncard = n + 1 + 1
hsn' : n + 1 + 2 < Nat.card α
hprim : IsPreprimitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s)
hα : Finite α
a : α
t : Set ↥(ofStabilizer G a)
left✝ : a ∈ s
hst : s = insert a (Subtype.val '' t)
ha' : a ∉ Subtype.val '' t
ht_prim : IsPreprimitive ↥(stabilizer G a) ↥(ofStabilizer G a)
this :
  IsPreprimitive ↥(fixingSubgroup G (insert a (Subtype.val '' t))) ↥(ofFixingSubgroup G (insert a (Subtype.val '' t)))
hGs' : IsPreprimitive ↥(fixingSubgroup (↥(stabilizer G a)) t) ↥(ofFixingSubgroup (↥(stabilizer G a)) t)
⊢ n + 2 < Nat.card ↥(ofStabilizer G a)

Tactic:
rw [← Nat.add_lt_add_iff_right, nat_card_ofStabilizer_add_one_eq]

Goal state after:
case refine_2
n : ℕ
hrec :
  ∀ {G : Type u_1} {α : Type u_2} [inst : Group G] [inst_1 : MulAction G α],
    IsPreprimitive G α →
      ∀ {s : Set α},
        s.ncard = n + 1 →
          n + 2 < Nat.card α →
            IsPreprimitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → Finite α → IsMultiplyPreprimitive G α (n + 2)
G : Type u_1
α : Type u_2
inst✝¹ : Group G
inst✝ : MulAction G α
hG : IsPreprimitive G α
s : Set α
hsn : s.ncard = n + 1 + 1
hsn' : n + 1 + 2 < Nat.card α
hprim : IsPreprimitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s)
hα : Finite α
a : α
t : Set ↥(ofStabilizer G a)
left✝ : a ∈ s
hst : s = insert a (Subtype.val '' t)
ha' : a ∉ Subtype.val '' t
ht_prim : IsPreprimitive ↥(stabilizer G a) ↥(ofStabilizer G a)
this :
  IsPreprimitive ↥(fixingSubgroup G (insert a (Subtype.val '' t))) ↥(ofFixingSubgroup G (insert a (Subtype.val '' t)))
hGs' : IsPreprimitive ↥(fixingSubgroup (↥(stabilizer G a)) t) ↥(ofFixingSubgroup (↥(stabilizer G a)) t)
⊢ n + 2 + 1 < Nat.card α
Module: Mathlib.GroupTheory.GroupAction.SubMulAction.Combination

Goal state before:
pp: α : Type u_2
inst✝³ : DecidableEq α
G : Type u_3
inst✝² : AddGroup G
inst✝¹ : AddAction G α
n : ℕ
hn : 1 ≤ n
hα : ↑n < ENat.card α
inst✝ : FaithfulVAdd G α
⊢ FaithfulVAdd G ↑(powersetCard α n)

Tactic:
rw [faithfulVAdd_iff]

Goal state after:
α : Type u_2
inst✝³ : DecidableEq α
G : Type u_3
inst✝² : AddGroup G
inst✝¹ : AddAction G α
n : ℕ
hn : 1 ≤ n
hα : ↑n < ENat.card α
inst✝ : FaithfulVAdd G α
⊢ ∀ (g : G), (∀ (a : ↑(powersetCard α n)), g +ᵥ a = a) → g = 0
Module: Mathlib.GroupTheory.GroupAction.SubMulAction.Combination

Goal state before:
pp: α : Type u_2
inst✝³ : DecidableEq α
G : Type u_3
inst✝² : AddGroup G
inst✝¹ : AddAction G α
n : ℕ
hn : 1 ≤ n
hα : ↑n < ENat.card α
inst✝ : FaithfulVAdd G α
⊢ FaithfulVAdd G ↑(powersetCard α n)

Tactic:
by
  rw [faithfulVAdd_iff]
  intro g hg
  apply AddAction.toPerm_injective (α := G) (β := α)
  rw [AddAction.toPerm_zero, ← addAction_faithful hn hα]
  exact Perm.ext_iff.mpr hg

Goal state after:
Module: Mathlib.GroupTheory.GroupAction.SubMulAction.Combination

Goal state before:
pp: G : Type u_1
inst✝² : Group G
α : Type u_2
inst✝¹ : MulAction G α
n : ℕ
inst✝ : DecidableEq α
hn : 1 ≤ n
hα : ↑n < ENat.card α
g : G
⊢ toPerm g = 1 ↔ toPerm g = 1

Tactic:
by
  refine ⟨fun h ↦ ?_, fun h ↦ ?_⟩
  · contrapose h with h
    have : ∃ a, (g • a : α) ≠ a := by simpa [Equiv.ext_iff] using h
    obtain ⟨a, ha⟩ := this
    obtain ⟨s, has, has'⟩ := exists_mem_notMem hn hα (Ne.symm ha)
    rw [Equiv.ext_iff, not_forall]
    use s
    contrapose! has'
    simp only [toPerm_apply, coe_one, id_eq] at has'
    rw [← has']
    simpa only [coe_smul, smul_mem_smul_finset_iff, ← mem_coe_iff]
  · simp only [Equiv.ext_iff, toPerm_apply] at h ⊢
    simp [Subtype.ext_iff, Finset.ext_iff, mem_smul_finset, h]

Goal state after:
Module: Mathlib.GroupTheory.GroupAction.Jordan

Goal state before:
pp: case inl
α : Type u_1
G : Subgroup (Perm α)
inst✝¹ : Fintype α
inst✝ : DecidableEq α
hG : IsPreprimitive (↥G) α
g : Perm α
h3g : g.IsThreeCycle
hg : g ∈ G
hα4 : Nat.card α ≤ 3
⊢ 3 = orderOf ⟨g, hg⟩

Tactic:
simp only [orderOf_mk, h3g.orderOf]

Goal state after:
Module: Mathlib.GroupTheory.GroupAction.Jordan

Goal state before:
pp: α : Type u_1
G : Subgroup (Perm α)
inst✝¹ : Fintype α
inst✝ : DecidableEq α
hG : IsPreprimitive (↥G) α
g : Perm α
h3g : g.IsThreeCycle
hg : g ∈ G
hα4 : Nat.card α ≥ 4
n : ℕ
hn : Nat.card α = n + 4
this : IsPretransitive ↥(fixingSubgroup (↥G) (↑g.support)ᶜ) ↥(ofFixingSubgroup (↥G) (↑g.support)ᶜ)
⊢ {x | x ∈ ofFixingSubgroup (↥G) (↑g.support)ᶜ}.card = g.support.card

Tactic:
apply congr_arg

Goal state after:
α : Type u_1
G : Subgroup (Perm α)
inst✝¹ : Fintype α
inst✝ : DecidableEq α
hG : IsPreprimitive (↥G) α
g : Perm α
h3g : g.IsThreeCycle
hg : g ∈ G
hα4 : Nat.card α ≥ 4
n : ℕ
hn : Nat.card α = n + 4
this : IsPretransitive ↥(fixingSubgroup (↥G) (↑g.support)ᶜ) ↥(ofFixingSubgroup (↥G) (↑g.support)ᶜ)
⊢ {x | x ∈ ofFixingSubgroup (↥G) (↑g.support)ᶜ} = g.support
Module: Mathlib.GroupTheory.GroupAction.SubMulAction.Combination

Goal state before:
pp: α : Type u_2
inst✝¹ : DecidableEq α
inst✝ : Fintype α
n : ℕ
h_three_le : 3 ≤ n
hn : n < Nat.card α
hα : Nat.card α ≠ 2 * n
this : IsPretransitive ↥(alternatingGroup α) ↑(powersetCard α n)
⊢ ↑n < ENat.card α

Tactic:
simpa using hn

Goal state after:
Module: Mathlib.GroupTheory.Perm.DomMulAct

Goal state before:
pp: α : Type u_1
ι : Type u_2
f : α → ι
inst✝³ : Fintype α
inst✝² : DecidableEq α
inst✝¹ : DecidableEq ι
inst✝ : Fintype ι
i : ι
x✝ : i ∈ Finset.univ
⊢ Nat.card (Perm { a // f a = i }) = (Fintype.card { a // f a = i })!

Tactic:
by rw [Nat.card_eq_fintype_card, Fintype.card_perm]

Goal state after:
Module: Mathlib.GroupTheory.Perm.DomMulAct

Goal state before:
pp: α : Type u_1
ι : Type u_2
f : α → ι
inst✝³ : Fintype α
inst✝² : DecidableEq α
inst✝¹ : DecidableEq ι
inst✝ : Fintype ι
⊢ ∏ a, Nat.card (Perm { a_1 // f a_1 = a }) = ∏ i, (Fintype.card { a // f a = i })!

Tactic:
exact Finset.prod_congr rfl fun i _ ↦ by rw [Nat.card_eq_fintype_card, Fintype.card_perm]

Goal state after:
Module: Mathlib.GroupTheory.Perm.DomMulAct

Goal state before:
pp: case h
α : Type u_1
ι : Type u_2
f : α → ι
inst✝² : Fintype α
inst✝¹ : DecidableEq α
inst✝ : DecidableEq ι
φ : α → ↥(Finset.image f Finset.univ) := Set.codRestrict f ↑(Finset.image f Finset.univ) ⋯
this : ∀ (g : Perm α), f ∘ ⇑g = f ↔ φ ∘ ⇑g = φ
i : ↥(Finset.image f Finset.univ)
ha✝ : i ∈ Finset.univ
⊢ (Fintype.card { a // φ a = i })! = (Fintype.card { a // f a = ↑i })!

Tactic:
apply congr_arg

Goal state after:
case h
α : Type u_1
ι : Type u_2
f : α → ι
inst✝² : Fintype α
inst✝¹ : DecidableEq α
inst✝ : DecidableEq ι
φ : α → ↥(Finset.image f Finset.univ) := ⋯
this : ∀ (g : Perm α), f ∘ ⇑g = f ↔ φ ∘ ⇑g = φ
i : ↥(Finset.image f Finset.univ)
ha✝ : i ∈ Finset.univ
⊢ Fintype.card { a // φ a = i } = Fintype.card { a // f a = ↑i }
Module: Mathlib.GroupTheory.Perm.Cycle.PossibleTypes

Goal state before:
pp: case h
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
m : Multiset ℕ
hc : m.sum ≤ Fintype.card α
h2c : ∀ a ∈ m, 2 ≤ a
hc' : m.toList.sum ≤ Fintype.card α
p : List (List α)
hp_length : List.map List.length p = m.toList
hp_nodup : ∀ s ∈ p, s.Nodup
hp_disj : List.Pairwise List.Disjoint p
hp2 : ∀ x ∈ p, 2 ≤ x.length
⊢ ↑(List.map (Finset.card ∘ support) (List.map (fun l ↦ l.formPerm) p)) = ↑m.toList

Tactic:
apply congr_arg

Goal state after:
case h
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
m : Multiset ℕ
hc : m.sum ≤ Fintype.card α
h2c : ∀ a ∈ m, 2 ≤ a
hc' : m.toList.sum ≤ Fintype.card α
p : List (List α)
hp_length : List.map List.length p = m.toList
hp_nodup : ∀ s ∈ p, s.Nodup
hp_disj : List.Pairwise List.Disjoint p
hp2 : ∀ x ∈ p, 2 ≤ x.length
⊢ List.map (Finset.card ∘ support) (List.map (fun l ↦ l.formPerm) p) = m.toList
Module: Mathlib.GroupTheory.Perm.Centralizer

Goal state before:
pp: α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g k c : Perm α
k_mem : k ∈ centralizer {g}
c_mem : c ∈ g.cycleFactorsFinset
this : g.cycleFactorsFinset = ConjAct.toConjAct k • g.cycleFactorsFinset
⊢ ↑g.cycleFactorsFinset = ConjAct.toConjAct k • ↑g.cycleFactorsFinset

Tactic:
conv_lhs => rw [this]

Goal state after:
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g k c : Perm α
k_mem : k ∈ centralizer {g}
c_mem : c ∈ g.cycleFactorsFinset
this : g.cycleFactorsFinset = ConjAct.toConjAct k • g.cycleFactorsFinset
⊢ ↑(ConjAct.toConjAct k • g.cycleFactorsFinset) = ConjAct.toConjAct k • ↑g.cycleFactorsFinset
Module: Mathlib.GroupTheory.Perm.ClosureSwap

Goal state before:
pp: α : Type u_2
inst✝ : DecidableEq α
S : Set (Equiv.Perm α)
hS : ∀ f ∈ S, f.IsSwap
supp : Set α
fin : supp.Finite
a : α
s : Set α
ih : ∀ {f : Equiv.Perm α}, (∀ (x : α), f x ∈ orbit (↥(closure S)) x) → (fixedBy α f)ᶜ ⊆ s → f ∈ closure S
f : Equiv.Perm α
hf : ∀ (x : α), f x ∈ orbit (↥(closure S)) x
supp_subset : (fixedBy α f)ᶜ ⊆ insert a s
⊢ f ∈ closure S

Tactic:
refine (mul_mem_cancel_left ((swap_mem_closure_isSwap hS).2 (hf a))).1
    (ih (fun b ↦ ?_) fun b hb ↦ ?_)

Goal state after:
case refine_1
α : Type u_2
inst✝ : DecidableEq α
S : Set (Equiv.Perm α)
hS : ∀ f ∈ S, f.IsSwap
supp : Set α
fin : supp.Finite
a : α
s : Set α
ih : ∀ {f : Equiv.Perm α}, (∀ (x : α), f x ∈ orbit (↥(closure S)) x) → (fixedBy α f)ᶜ ⊆ s → f ∈ closure S
f : Equiv.Perm α
hf : ∀ (x : α), f x ∈ orbit (↥(closure S)) x
supp_subset : (fixedBy α f)ᶜ ⊆ insert a s
b : α
⊢ (Equiv.swap (f a) a * f) b ∈ orbit (↥(closure S)) b

case refine_2
α : Type u_2
inst✝ : DecidableEq α
S : Set (Equiv.Perm α)
hS : ∀ f ∈ S, f.IsSwap
supp : Set α
fin : supp.Finite
a : α
s : Set α
ih : ∀ {f : Equiv.Perm α}, (∀ (x : α), f x ∈ orbit (↥(closure S)) x) → (fixedBy α f)ᶜ ⊆ s → f ∈ closure S
f : Equiv.Perm α
hf : ∀ (x : α), f x ∈ orbit (↥(closure S)) x
supp_subset : (fixedBy α f)ᶜ ⊆ insert a s
b : α
hb : b ∈ (fixedBy α (Equiv.swap (f a) a * f))ᶜ
⊢ b ∈ s
Module: Mathlib.GroupTheory.Perm.ClosureSwap

Goal state before:
pp: case pos
α : Type u_2
inst✝ : DecidableEq α
f : Equiv.Perm α
x : α
h : x = f x
⊢ Equiv.refl α ∈ closure fun x ↦ ∃ x_1 y, x_1 ≠ y ∧ x = Equiv.swap x_1 y

Tactic:
apply Subgroup.one_mem

Goal state after:
Module: Mathlib.GroupTheory.ResiduallyFinite

Goal state before:
pp: G : Type u_1
inst✝ : Group G
⊢ ResiduallyFinite G ↔ ∀ (g : G), (∀ (H : FiniteIndexNormalSubgroup G), g ∈ H) → g = 1

Tactic:
residuallyFinite_def,

Goal state after:
G : Type u_1
inst✝ : Group G
⊢ ⨅ H, H.toSubgroup = ⊥ ↔ ∀ (g : G), (∀ (H : FiniteIndexNormalSubgroup G), g ∈ H) → g = 1
Module: Mathlib.GroupTheory.SpecificGroups.Alternating.Centralizer

Goal state before:
pp: α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
m : Multiset ℕ
⊢ (if Even (m.sum + m.card) then
      #{g | g.cycleType = m} * ((Fintype.card α - m.sum)! * m.prod * ∏ n ∈ m.toFinset, (Multiset.count n m)!)
    else 0 * ((Fintype.card α - m.sum)! * m.prod * ∏ n ∈ m.toFinset, (Multiset.count n m)!)) =
    if (m.sum ≤ Fintype.card α ∧ ∀ a ∈ m, 2 ≤ a) ∧ Even (m.sum + m.card) then (Fintype.card α)! else 0

Tactic:
zero_mul

Goal state after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
m : Multiset ℕ
⊢ (if Even (m.sum + m.card) then
      #{g | g.cycleType = m} * ((Fintype.card α - m.sum)! * m.prod * ∏ n ∈ m.toFinset, (Multiset.count n m)!)
    else 0) =
    if (m.sum ≤ Fintype.card α ∧ ∀ a ∈ m, 2 ≤ a) ∧ Even (m.sum + m.card) then (Fintype.card α)! else 0
Module: Mathlib.GroupTheory.Perm.Centralizer

Goal state before:
pp: α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g : Perm α
⊢ (Fintype.card α - g.cycleType.sum)! * ∏ i, Fintype.card ↥(zpowers ↑i) =
    (Fintype.card α - g.cycleType.sum)! * g.cycleType.prod

Tactic:
apply congr_arg

Goal state after:
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g : Perm α
⊢ ∏ i, Fintype.card ↥(zpowers ↑i) = g.cycleType.prod
Module: Mathlib.GroupTheory.Perm.Centralizer

Goal state before:
pp: α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
m : Multiset ℕ
⊢ (∀ ⦃x : Perm α⦄, x ∈ Finset.univ → ¬x.cycleType = m) ↔ ¬(m.sum ≤ Fintype.card α ∧ ∀ a ∈ m, 2 ≤ a)

Tactic:
← exists_with_cycleType_iff,

Goal state after:
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
m : Multiset ℕ
⊢ (∀ ⦃x : Perm α⦄, x ∈ Finset.univ → ¬x.cycleType = m) ↔ ¬∃ g, g.cycleType = m
Module: Mathlib.GroupTheory.Perm.Centralizer

Goal state before:
pp: case neg
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
m : Multiset ℕ
hm : ¬(m.sum ≤ Fintype.card α ∧ ∀ a ∈ m, 2 ≤ a)
⊢ 0 * ((Fintype.card α - m.sum)! * m.prod * ∏ n ∈ m.toFinset, (Multiset.count n m)!) = 0

Tactic:
zero_mul

Goal state after:
case neg
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
m : Multiset ℕ
hm : ¬(m.sum ≤ Fintype.card α ∧ ∀ a ∈ m, 2 ≤ a)
⊢ 0 = 0
Module: Mathlib.GroupTheory.SpecificGroups.Alternating.KleinFour

Goal state before:
pp: α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
hα4 : Nat.card α = 4
S : Sylow 2 ↥(alternatingGroup α)
k : ↥(alternatingGroup α)
hk : k ∈ ↑S
n : ℕ
hn : orderOf ⟨k, hk⟩ = 2 ^ n
⊢ orderOf ↑k = 2 ^ n

Tactic:
simpa using hn

Goal state after:
Module: Mathlib.GroupTheory.SpecificGroups.Quaternion

Goal state before:
pp: case inr
n : ℕ
hn : NeZero n
⊢ Monoid.exponent (QuaternionGroup n) = lcm (2 * n) 4

Tactic:
apply Nat.dvd_antisymm

Goal state after:
case inr.a
n : ℕ
hn : NeZero n
⊢ Monoid.exponent (QuaternionGroup n) ∣ lcm (2 * n) 4

case inr.a
n : ℕ
hn : NeZero n
⊢ lcm (2 * n) 4 ∣ Monoid.exponent (QuaternionGroup n)
Module: Mathlib.GroupTheory.SpecificGroups.ZGroup

Goal state before:
pp: case neg.inr
G : Type u_1
inst✝⁴ : Group G
p : ℕ
inst✝³ : Fact (Nat.Prime p)
inst✝² : IsCyclic G
K : Type u_4
inst✝¹ : Group K
inst✝ : MulDistribMulAction K G
hGK : (Nat.card G).Coprime (Nat.card K)
hc : ¬Nat.card G = 0
this : Finite G
ϕ : K →* ZMod (Nat.card G) := MulDistribMulAction.toMonoidHomZModOfIsCyclic G K ⋯
h : ∀ (g : G) (k : K) (n : ℤ), ϕ k - 1 = ↑n → k • g * g⁻¹ = g ^ n
hG : ∀ (k : K), ϕ k = 1 ∨ IsUnit (ϕ k - 1)
k : K
hk : ¬ϕ k = 1
u v : ZMod (Nat.card G)
hvu : ↑(v.cast * u.cast) = ↑1
hu : ↑u.cast = ϕ k - 1
⊢ (∀ (g : G) (k : K), k • g * g⁻¹ = 1) ∨ ∀ (g : G), ∃ k q, k • q * q⁻¹ = g

Tactic:
ZMod.intCast_eq_intCast_iff

Goal state after:
case neg.inr
G : Type u_1
inst✝⁴ : Group G
p : ℕ
inst✝³ : Fact (Nat.Prime p)
inst✝² : IsCyclic G
K : Type u_4
inst✝¹ : Group K
inst✝ : MulDistribMulAction K G
hGK : (Nat.card G).Coprime (Nat.card K)
hc : ¬Nat.card G = 0
this : Finite G
ϕ : K →* ZMod (Nat.card G) := MulDistribMulAction.toMonoidHomZModOfIsCyclic G K ⋯
h : ∀ (g : G) (k : K) (n : ℤ), ϕ k - 1 = ↑n → k • g * g⁻¹ = g ^ n
hG : ∀ (k : K), ϕ k = 1 ∨ IsUnit (ϕ k - 1)
k : K
hk : ¬ϕ k = 1
u v : ZMod (Nat.card G)
hvu : v.cast * u.cast ≡ 1 [ZMOD ↑(Nat.card G)]
hu : ↑u.cast = ϕ k - 1
⊢ (∀ (g : G) (k : K), k • g * g⁻¹ = 1) ∨ ∀ (g : G), ∃ k q, k • q * q⁻¹ = g
Module: Mathlib.GroupTheory.SpecificGroups.ZGroup

Goal state before:
pp: case refine_2
G : Type u_1
inst✝¹ : Group G
inst✝ : Finite G
N H : Subgroup G
φ : ↥H →* MulAut ↥N
e : G ≃* ↥N ⋊[φ] ↥H
hH : IsCyclic ↥H
hN : IsCyclic ↥N
hHN : (Nat.card ↥N).Coprime (Nat.card ↥H)
⊢ IsZGroup G

Tactic:
have : IsZGroup (N ⋊[φ] H) :=
      isZGroup_of_coprime SemidirectProduct.range_inl_eq_ker_rightHom.ge hHN

Goal state after:
case refine_2
G : Type u_1
inst✝¹ : Group G
inst✝ : Finite G
N H : Subgroup G
φ : ↥H →* MulAut ↥N
e : G ≃* ↥N ⋊[φ] ↥H
hH : IsCyclic ↥H
hN : IsCyclic ↥N
hHN : (Nat.card ↥N).Coprime (Nat.card ↥H)
this : IsZGroup (↥N ⋊[φ] ↥H)
⊢ IsZGroup G
Module: Mathlib.Probability.Kernel.Basic

Goal state before:
pp: α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
κ✝ : Kernel α β
γ : Type u_4
mγ : MeasurableSpace γ
f : γ → β
κ : Kernel α β
inst✝ : IsSFiniteKernel κ
hf : MeasurableEmbedding f
a : α
t : Set γ
ht : MeasurableSet t
⊢ ∑' (i : ℕ), (Measure.comap f ((κ.seq i) a)) t = ∑' (i : ℕ), ((κ.seq i) a) (f '' t)

Tactic:
congr with n : 1

Goal state after:
case e_f
α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
κ✝ : Kernel α β
γ : Type u_4
mγ : MeasurableSpace γ
f : γ → β
κ : Kernel α β
inst✝ : IsSFiniteKernel κ
hf : MeasurableEmbedding f
a : α
t : Set γ
ht : MeasurableSet t
n : ℕ
⊢ (Measure.comap f ((κ.seq n) a)) t = ((κ.seq n) a) (f '' t)
Module: Mathlib.Probability.Kernel.MeasurableLIntegral

Goal state before:
pp: case iUnion
α : Type u_1
β : Type u_2
mα : MeasurableSpace α
mβ : MeasurableSpace β
κ : Kernel α β
t : Set (α × β)
hκs : ∀ (a : α), IsFiniteMeasure (κ a)
f : ℕ → Set (α × β)
h_disj : Pairwise (Disjoint on f)
hf_meas : ∀ (i : ℕ), MeasurableSet (f i)
hf : ∀ (i : ℕ), Measurable fun a ↦ (κ a) (Prod.mk a ⁻¹' f i)
⊢ Measurable fun a ↦ (κ a) (Prod.mk a ⁻¹' ⋃ i, f i)

Tactic:
have (a : α) : κ a (Prod.mk a ⁻¹' ⋃ i, f i) = ∑' i, κ a (Prod.mk a ⁻¹' f i) := by
      rw [preimage_iUnion, measure_iUnion]
      · exact h_disj.mono fun _ _ ↦ .preimage _
      · exact fun i ↦ measurable_prodMk_left (hf_meas i)
    simpa only [this] using Measurable.tsum hf

Goal state after:
Module: Mathlib.Probability.Kernel.Composition.MapComap

Goal state before:
pp: α : Type u_1
β : Type u_2
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
δ : Type u_5
mγ : MeasurableSpace γ
mδ : MeasurableSpace δ
κ : Kernel α β
f : β → γ
hf : Measurable f
g : γ → δ
hg : Measurable g
x : α
⊢ (κ.map (g ∘ f)) x = ((κ.map f).map g) x

Tactic:
map_apply _ hg,

Goal state after:
α : Type u_1
β : Type u_2
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
δ : Type u_5
mγ : MeasurableSpace γ
mδ : MeasurableSpace δ
κ : Kernel α β
f : β → γ
hf : Measurable f
g : γ → δ
hg : Measurable g
x : α
⊢ (κ.map (g ∘ f)) x = Measure.map g ((κ.map f) x)