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

Goal state before:
pp: case succ
k : ℕ
hrec :
  ∀ {G : Type u_1} [inst : Group G] {α : Type u_2} [inst_1 : MulAction G α] [Finite α],
    IsMultiplyPretransitive G α k →
      ∀ {s : Set α}, s.ncard = k → (fixingSubgroup G s).index * (Nat.card α - k)! = (Nat.card α)!
G : Type u_1
inst✝² : Group G
α : Type u_2
inst✝¹ : MulAction G α
inst✝ : Finite α
Hk : IsMultiplyPretransitive G α (k + 1)
s : Set α
hs : s.ncard = k + 1
hGX : IsPretransitive G α
a : α
has : a ∈ s
t : Set ↥(ofStabilizer G a) := Subtype.val ⁻¹' s
hat : Subtype.val '' t = s \ {a}
⊢ (fixingSubgroup G s).index * (Nat.card α - (k + 1))! = (Nat.card α)!

Tactic:
have hat' : s = insert a (Subtype.val '' t) := by
      rw [hat, Set.insert_sdiff_singleton, Set.insert_eq_of_mem has]

Goal state after:
case succ
k : ℕ
hrec :
  ∀ {G : Type u_1} [inst : Group G] {α : Type u_2} [inst_1 : MulAction G α] [Finite α],
    IsMultiplyPretransitive G α k →
      ∀ {s : Set α}, s.ncard = k → (fixingSubgroup G s).index * (Nat.card α - k)! = (Nat.card α)!
G : Type u_1
inst✝² : Group G
α : Type u_2
inst✝¹ : MulAction G α
inst✝ : Finite α
Hk : IsMultiplyPretransitive G α (k + 1)
s : Set α
hs : s.ncard = k + 1
hGX : IsPretransitive G α
a : α
has : a ∈ s
t : Set ↥(ofStabilizer G a) := Subtype.val ⁻¹' s
hat : Subtype.val '' t = s \ {a}
hat' : s = insert a (Subtype.val '' t)
⊢ (fixingSubgroup G s).index * (Nat.card α - (k + 1))! = (Nat.card α)!
Module: Mathlib.GroupTheory.GroupAction.Jordan

Goal state before:
pp: n : ℕ
hrec :
  ∀ m < n,
    ∀ {G : Type u_1} {α : Type u_2} [inst : Group G] [inst_1 : MulAction G α],
      IsPreprimitive G α →
        ∀ {s : Set α},
          s.ncard = m + 1 →
            m + 2 < Nat.card α →
              (IsPretransitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → IsMultiplyPretransitive G α 2) ∧
                (IsPreprimitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → IsMultiplyPreprimitive G α 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
hsn' : n + 2 < Nat.card α
this : Finite α
hs_ne_univ : s ≠ Set.univ
⊢ s.Nonempty

Tactic:
simp [← Set.ncard_pos s.toFinite, hsn]

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

Goal state before:
pp: n : ℕ
hrec :
  ∀ m < n,
    ∀ {G : Type u_1} {α : Type u_2} [inst : Group G] [inst_1 : MulAction G α],
      IsPreprimitive G α →
        ∀ {s : Set α},
          s.ncard = m + 1 →
            m + 2 < Nat.card α →
              (IsPretransitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → IsMultiplyPretransitive G α 2) ∧
                (IsPreprimitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → IsMultiplyPreprimitive G α 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
hsn' : n + 2 < Nat.card α
this : Finite α
hs_ne_univ : s ≠ Set.univ
hs_nonempty : s.Nonempty
hn : n + 1 ≥ 2
hn1 : 2 * (n + 1) < Nat.card α
a : α
ha : a ∈ s
b : α
hb : b ∈ s
hab : a ≠ b
g : G
hga : a ∈ g • s
hgb : b ∉ g • s
t : Set α := s ∩ g • s
ht : t.Finite
htm : t.ncard = t.ncard - 1 + 1
⊢ t.ncard - 1 < n

Tactic:
Nat.lt_iff_add_one_le,

Goal state after:
n : ℕ
hrec :
  ∀ m < n,
    ∀ {G : Type u_1} {α : Type u_2} [inst : Group G] [inst_1 : MulAction G α],
      IsPreprimitive G α →
        ∀ {s : Set α},
          s.ncard = m + 1 →
            m + 2 < Nat.card α →
              (IsPretransitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → IsMultiplyPretransitive G α 2) ∧
                (IsPreprimitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → IsMultiplyPreprimitive G α 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
hsn' : n + 2 < Nat.card α
this : Finite α
hs_ne_univ : s ≠ Set.univ
hs_nonempty : s.Nonempty
hn : n + 1 ≥ 2
hn1 : 2 * (n + 1) < Nat.card α
a : α
ha : a ∈ s
b : α
hb : b ∈ s
hab : a ≠ b
g : G
hga : a ∈ g • s
hgb : b ∉ g • s
t : Set α := s ∩ g • s
ht : t.Finite
htm : t.ncard = t.ncard - 1 + 1
⊢ t.ncard - 1 + 1 ≤ n
Module: Mathlib.GroupTheory.GroupAction.SubMulAction.OfFixingSubgroup

Goal state before:
pp: 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 ∈ (s ∪ g • s)ᶜ
⊢ IsPretransitive ↥(fixingSubgroup M (s ∩ g • s)) ↥(ofFixingSubgroup M (s ∩ g • s))

Tactic:
rw [Set.compl_union] at ha

Goal state after:
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
⊢ IsPretransitive ↥(fixingSubgroup M (s ∩ g • s)) ↥(ofFixingSubgroup M (s ∩ g • s))
Module: Mathlib.GroupTheory.GroupAction.Jordan

Goal state before:
pp: n : ℕ
hrec :
  ∀ m < n,
    ∀ {G : Type u_1} {α : Type u_2} [inst : Group G] [inst_1 : MulAction G α],
      IsPreprimitive G α →
        ∀ {s : Set α},
          s.ncard = m + 1 →
            m + 2 < Nat.card α →
              (IsPretransitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → IsMultiplyPretransitive G α 2) ∧
                (IsPreprimitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → IsMultiplyPreprimitive G α 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
hsn' : n + 2 < Nat.card α
this✝ : Finite α
hs_ne_univ : s ≠ Set.univ
hs_nonempty : s.Nonempty
hn : n + 1 ≥ 2
hn1 : 2 * (n + 1) < Nat.card α
a : α
ha : a ∈ s
b : α
hb : b ∈ s
hab : a ≠ b
g : G
hga : a ∈ g • s
hgb : b ∉ g • s
t : Set α := s ∩ g • s
ht : t.Finite
htm : t.ncard = t.ncard - 1 + 1
hmn : t.ncard - 1 < n
htm' : t.ncard - 1 + 2 < Nat.card α
this : IsPretransitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → IsMultiplyPretransitive G α 2
⊢ (IsPretransitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → IsMultiplyPretransitive G α 2) ∧
    (IsPreprimitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → IsMultiplyPreprimitive G α 2)

Tactic:
refine ⟨this, fun hs_prim ↦ ?_⟩
      have ht_prim : IsPreprimitive (fixingSubgroup G t) (ofFixingSubgroup G t) := by
        apply IsPreprimitive.isPreprimitive_ofFixingSubgroup_inter hs_prim
        apply Set.union_ne_univ_of_ncard_add_ncard_lt
        rwa [Set.ncard_smul_set, hsn, ← two_mul]
      apply (hrec (t.ncard - 1) hmn hG htm htm').2 ht_prim

Goal state after:
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
hφ : Function.Surjective φ
f : α →ₑ[φ] β
hf : Function.Bijective ⇑f
n : ℕ
H : IsMultiplyPreprimitive N β n
s : Set α
hs : s.encard + 1 = ↑n
t : Set β := ⇑f '' s
x✝ : ↥(fixingSubgroup M s)
g : M
hg : ∀ y ∈ s, g • y = y
x : α
hx : x ∈ s
hy : f x ∈ t
⊢ φ g • f x = f x

Tactic:
← map_smulₛₗ,

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
hφ : Function.Surjective φ
f : α →ₑ[φ] β
hf : Function.Bijective ⇑f
n : ℕ
H : IsMultiplyPreprimitive N β n
s : Set α
hs : s.encard + 1 = ↑n
t : Set β := ⇑f '' s
x✝ : ↥(fixingSubgroup M s)
g : M
hg : ∀ y ∈ s, g • y = y
x : α
hx : x ∈ s
hy : f x ∈ t
⊢ f (g • x) = f x
Module: Mathlib.GroupTheory.Perm.MaximalSubgroups

Goal state before:
pp: case refine_2
α : Type u_2
s : Set α
inst✝ : DecidablePred fun x ↦ x ∈ s
g : Perm ↑s
g' : α
a : g' ∈ s
⊢ ∃ y ∈ s, (ofSubtype g) y = g'

Tactic:
· use (g⁻¹ ⟨g', a⟩)
    simp

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

Goal state before:
pp: n : ℕ
hrec :
  ∀ m < n,
    ∀ {G : Type u_1} {α : Type u_2} [inst : Group G] [inst_1 : MulAction G α],
      IsPreprimitive G α →
        ∀ {s : Set α},
          s.ncard = m + 1 →
            m + 2 < Nat.card α →
              (IsPretransitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → IsMultiplyPretransitive G α 2) ∧
                (IsPreprimitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → IsMultiplyPreprimitive G α 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
hsn' : n + 2 < Nat.card α
this : Finite α
hs_ne_univ : s ≠ Set.univ
hs_nonempty : s.Nonempty
hn : n + 1 ≥ 2
hn2 : 2 * (n + 1) ≥ Nat.card α
a : α
ha✝ : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
hab : a ≠ b
g : G
hga : a ∈ g • sᶜ
hgb : b ∉ g • sᶜ
t : Set α := s ∩ g • s
ha : a ∉ s ∪ g • s
htm : t.ncard = t.ncard - 1 + 1
⊢ t.ncard - 1 < n

Tactic:
Nat.lt_iff_add_one_le,

Goal state after:
n : ℕ
hrec :
  ∀ m < n,
    ∀ {G : Type u_1} {α : Type u_2} [inst : Group G] [inst_1 : MulAction G α],
      IsPreprimitive G α →
        ∀ {s : Set α},
          s.ncard = m + 1 →
            m + 2 < Nat.card α →
              (IsPretransitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → IsMultiplyPretransitive G α 2) ∧
                (IsPreprimitive ↥(fixingSubgroup G s) ↥(ofFixingSubgroup G s) → IsMultiplyPreprimitive G α 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
hsn' : n + 2 < Nat.card α
this : Finite α
hs_ne_univ : s ≠ Set.univ
hs_nonempty : s.Nonempty
hn : n + 1 ≥ 2
hn2 : 2 * (n + 1) ≥ Nat.card α
a : α
ha✝ : a ∈ sᶜ
b : α
hb : b ∈ sᶜ
hab : a ≠ b
g : G
hga : a ∈ g • sᶜ
hgb : b ∉ g • sᶜ
t : Set α := s ∩ g • s
ha : a ∉ s ∪ g • s
htm : t.ncard = t.ncard - 1 + 1
⊢ t.ncard - 1 + 1 ≤ n
Module: Mathlib.GroupTheory.GroupAction.MultiplePrimitivity

Goal state before:
pp: case right.hf
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
hφ : Function.Surjective φ
f : α →ₑ[φ] β
hf : Function.Bijective ⇑f
n : ℕ
H : IsMultiplyPreprimitive N β n
s : Set α
hs : s.encard + 1 = ↑n
t : Set β := ⇑f '' s
ψ : ↥(fixingSubgroup M s) → ↥(fixingSubgroup N t) :=
  fun x ↦
    match x with
    | ⟨g, hg⟩ => ⟨φ g, ⋯⟩
g : ↥(ofFixingSubgroup M s) →ₑ[ψ] ↥(ofFixingSubgroup N t) := { toFun := fun x ↦ ⟨f ↑x, ⋯⟩, map_smul' := ⋯ }
⊢ Function.Bijective ⇑g

Tactic:
· constructor
      · rintro ⟨x, hx⟩ ⟨y, hy⟩ h
        suffices f x = f y by
          simpa [← Subtype.coe_inj, hf.injective.eq_iff] using! this
        simpa only [g, ← Subtype.coe_inj] using! h
      · rintro ⟨x, hx⟩
        obtain ⟨y, rfl⟩ := hf.surjective x
        suffices y ∈ ofFixingSubgroup M s by
          exact ⟨⟨y, this⟩, rfl⟩
        simp only [mem_ofFixingSubgroup_iff, Set.mem_image, not_exists, not_and, t] at hx ⊢
        exact fun hy ↦ hx y hy rfl

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

Goal state before:
pp: case hs'
M : Type u_1
α : Type u_2
inst✝¹ : Group M
inst✝ : MulAction M α
s : Set α
G : Subgroup M
hG : stabilizer M s < G
moves : ∀ {s : Set α}, ∀ a ∈ s, ∀ b ∈ s, ∃ g ∈ stabilizer M s, g • a = b
⊢ ∀ a ∈ sᶜ, ∀ b ∈ sᶜ, ∃ g, g • a = b

Tactic:
intro a ha b hb
    obtain ⟨g, hg, rfl⟩ := moves a ha b hb
    rw [stabilizer_compl] at hg
    exact ⟨⟨g, hG.le hg⟩, rfl⟩

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

Goal state before:
pp: M : Type u_1
α : Type u_2
inst✝³ : Group M
inst✝² : MulAction M α
s : Set α
inst✝¹ : Finite α
inst✝ : IsMultiplyPretransitive M α (s.ncard + 1)
G : Subgroup M
hG : stabilizer M s ≤ G
B : Set α
hBs : ¬B ⊆ s
hBsc : ¬B ⊆ sᶜ
hB : IsBlock (↥G) B
a : α
ha : a ∈ B
ha' : a ∈ s
b : α
hb : b ∈ B
hb' : b ∈ sᶜ
k : M
hk : k ∈ fixingSubgroup M s
hx' : ⟨k, hk⟩ • b ∈ sᶜ
⊢ k ∈ stabilizer M s

Tactic:
exact MulAction.fixingSubgroup_le_stabilizer _ _ hk

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 ≤ 3
this : 3 = orderOf ⟨g, hg⟩
⊢ 3 ∣ Nat.card ↥G

Tactic:
rw [this, Nat.card_eq_fintype_card]
      exact orderOf_dvd_card

Goal state after:
Module: Mathlib.GroupTheory.IsPerfect

Goal state before:
pp: G : Type u_1
inst✝ : Group G
⊢ ⁅⊤, ⊤⁆ = ⊤.subtype.range ↔ _root_.commutator G = ⊤

Tactic:
subtype_range,

Goal state after:
G : Type u_1
inst✝ : Group G
⊢ ⁅⊤, ⊤⁆ = ⊤ ↔ _root_.commutator G = ⊤
Module: Mathlib.GroupTheory.HNNExtension

Goal state before:
pp: G : Type u_1
inst✝ : Group G
A B : Subgroup G
φ : ↥A ≃* ↥B
motive : HNNExtension G A B φ → Prop
x : HNNExtension G A B φ
of : ∀ (g : G), motive (HNNExtension.of g)
t : motive HNNExtension.t
mul : ∀ (x y : HNNExtension G A B φ), motive x → motive y → motive (x * y)
inv : ∀ (x : HNNExtension G A B φ), motive x → motive x⁻¹
S : Subgroup (HNNExtension G A B φ) := ⋯
a : ↥A
⊢ ↑(⟨HNNExtension.t, t⟩ * (HNNExtension.of.codRestrict S of) ↑a) =
    ↑((HNNExtension.of.codRestrict S of) ↑(φ a) * ⟨HNNExtension.t, t⟩)

Tactic:
simp [equiv_eq_conj, mul_assoc]

Goal state after:
Module: Mathlib.GroupTheory.MonoidLocalization.Order

Goal state before:
pp: α : Type u_1
inst✝² : CommMonoid α
inst✝¹ : PartialOrder α
inst✝ : IsOrderedCancelMonoid α
s : Submonoid α
a₁✝ b₁✝ : α
a₂✝ b₂✝ : ↥s
a b : Localization s
a₁ b₁ : α
a₂ b₂ : ↥s
c₁ d₁ : α
c₂ d₂ : ↥s
hab : (r s) (a₁, a₂) (b₁, b₂)
hcd : (r s) (c₁, c₂) (d₁, d₂)
e : ↥s
he : ↑e * (↑(b₁, b₂).2 * (a₁, a₂).1) = ↑e * (↑(a₁, a₂).2 * (b₁, b₂).1)
f : ↥s
hf : ↑f * (↑(d₁, d₂).2 * (c₁, c₂).1) = ↑f * (↑(c₁, c₂).2 * (d₁, d₂).1)
⊢ ↑c₂ * a₁ ≤ ↑a₂ * c₁ ↔ ↑d₂ * b₁ ≤ ↑b₂ * d₁

Tactic:
simp only [mul_right_inj] at he hf

Goal state after:
α : Type u_1
inst✝² : CommMonoid α
inst✝¹ : PartialOrder α
inst✝ : IsOrderedCancelMonoid α
s : Submonoid α
a₁✝ b₁✝ : α
a₂✝ b₂✝ : ↥s
a b : Localization s
a₁ b₁ : α
a₂ b₂ : ↥s
c₁ d₁ : α
c₂ d₂ : ↥s
hab : (r s) (a₁, a₂) (b₁, b₂)
hcd : (r s) (c₁, c₂) (d₁, d₂)
e f : ↥s
he : ↑b₂ * a₁ = ↑a₂ * b₁
hf : ↑d₂ * c₁ = ↑c₂ * d₁
⊢ ↑c₂ * a₁ ≤ ↑a₂ * c₁ ↔ ↑d₂ * b₁ ≤ ↑b₂ * d₁
Module: Mathlib.GroupTheory.MonoidLocalization.Order

Goal state before:
pp: α : Type u_1
inst✝² : CommMonoid α
inst✝¹ : PartialOrder α
inst✝ : IsOrderedCancelMonoid α
s : Submonoid α
a₁✝ b₁✝ : α
a₂✝ b₂✝ : ↥s
a b : Localization s
a₁ b₁ : α
a₂ b₂ : ↥s
c₁ d₁ : α
c₂ d₂ : ↥s
hab : (r s) (a₁, a₂) (b₁, b₂)
hcd : (r s) (c₁, c₂) (d₁, d₂)
e : ↥s
he : ↑e * (↑(b₁, b₂).2 * (a₁, a₂).1) = ↑e * (↑(a₁, a₂).2 * (b₁, b₂).1)
f : ↥s
hf : ↑f * (↑(d₁, d₂).2 * (c₁, c₂).1) = ↑f * (↑(c₁, c₂).2 * (d₁, d₂).1)
⊢ ↑c₂ * a₁ < ↑a₂ * c₁ ↔ ↑d₂ * b₁ < ↑b₂ * d₁

Tactic:
simp only [mul_right_inj] at he hf

Goal state after:
α : Type u_1
inst✝² : CommMonoid α
inst✝¹ : PartialOrder α
inst✝ : IsOrderedCancelMonoid α
s : Submonoid α
a₁✝ b₁✝ : α
a₂✝ b₂✝ : ↥s
a b : Localization s
a₁ b₁ : α
a₂ b₂ : ↥s
c₁ d₁ : α
c₂ d₂ : ↥s
hab : (r s) (a₁, a₂) (b₁, b₂)
hcd : (r s) (c₁, c₂) (d₁, d₂)
e f : ↥s
he : ↑b₂ * a₁ = ↑a₂ * b₁
hf : ↑d₂ * c₁ = ↑c₂ * d₁
⊢ ↑c₂ * a₁ < ↑a₂ * c₁ ↔ ↑d₂ * b₁ < ↑b₂ * d₁
Module: Mathlib.GroupTheory.HNNExtension

Goal state before:
pp: G : Type u_1
inst✝² : Group G
A B : Subgroup G
φ : ↥A ≃* ↥B
H : Type u_2
inst✝¹ : Group H
M : Type u_3
inst✝ : Monoid M
d : TransversalPair G A B
u : ℤˣ
w : NormalWord d
this : (p : Prop) → Decidable p := Classical.dec
g' : ↥(toSubgroup A B (-u)) × ↑(d.set u) := unitsSMulGroup φ d u w.head
h : w.head ∈ toSubgroup A B u → ∀ (x : G), ¬w.toList.head? = some (-u, x)
u' : ℤˣ
x : G
hx : w.toList.head? = some (u', x)
hmem : ↑(⋯.equiv w.head).2 ∈ toSubgroup A B u
⊢ u = u'

Tactic:
have : w.head ∈ toSubgroup A B u := by
          have := (d.compl u).rightCosetEquivalence_equiv_snd w.head
          rw [RightCosetEquivalence, rightCoset_eq_iff, mul_mem_cancel_left hmem] at this
          simp_all

Goal state after:
G : Type u_1
inst✝² : Group G
A B : Subgroup G
φ : ↥A ≃* ↥B
H : Type u_2
inst✝¹ : Group H
M : Type u_3
inst✝ : Monoid M
d : TransversalPair G A B
u : ℤˣ
w : NormalWord d
this✝ : (p : Prop) → Decidable p := Classical.dec
g' : ↥(toSubgroup A B (-u)) × ↑(d.set u) := unitsSMulGroup φ d u w.head
h : w.head ∈ toSubgroup A B u → ∀ (x : G), ¬w.toList.head? = some (-u, x)
u' : ℤˣ
x : G
hx : w.toList.head? = some (u', x)
hmem : ↑(⋯.equiv w.head).2 ∈ toSubgroup A B u
this : w.head ∈ toSubgroup A B u
⊢ u = u'
Module: Mathlib.GroupTheory.NoncommCoprod

Goal state before:
pp: case refine_4
M : Type u_4
N : Type u_5
P : Type u_6
inst✝² : Group M
inst✝¹ : Group N
inst✝ : Group P
f : M →* P
g : N →* P
comm : ∀ (m : M) (n : N), Commute (f m) (g n)
hf : ∀ (a : M), f a = 1 → a = 1
hg : ∀ (a : N), g a = 1 → a = 1
hp : f.range ⊓ g.range ≤ ⊥
⊢ ∀ (a : M) (b : N), f a * g b = 1 → a = 1 ∧ b = 1

Tactic:
a

Goal state after:
case refine_4
M : Type u_4
N : Type u_5
P : Type u_6
inst✝² : Group M
inst✝¹ : Group N
inst✝ : Group P
f : M →* P
g : N →* P
comm : ∀ (m : M) (n : N), Commute (f m) (g n)
hf : ∀ (a : M), f a = 1 → a = 1
hg : ∀ (a : N), g a = 1 → a = 1
hp : f.range ⊓ g.range ≤ ⊥
a : M
⊢ ∀ (b : N), f a * g b = 1 → a = 1 ∧ b = 1
Module: Mathlib.GroupTheory.HNNExtension

Goal state before:
pp: case pos.cons.refl.inl
G : Type u_1
inst✝ : Group G
A B : Subgroup G
φ : ↥A ≃* ↥B
d : TransversalPair G A B
g✝ : G
w✝ : NormalWord d
h1✝ : w✝.head ∈ d.set { val := -↑1, inv := -↑1⁻¹, val_inv := ⋯, inv_val := ⋯ }
h2✝ :
  ∀ u' ∈ Option.map Prod.fst w✝.toList.head?,
    w✝.head ∈ toSubgroup A B { val := -↑1, inv := -↑1⁻¹, val_inv := ⋯, inv_val := ⋯ } →
      { val := -↑1, inv := -↑1⁻¹, val_inv := ⋯, inv_val := ⋯ } = u'
hcan : Cancels 1 (cons g✝ { val := -↑1, inv := -↑1⁻¹, val_inv := ⋯, inv_val := ⋯ } w✝ h1✝ h2✝)
a✝ :
  cons g✝ { val := -↑1, inv := -↑1⁻¹, val_inv := ⋯, inv_val := ⋯ } w✝ h1✝ h2✝ = w✝ →
    ReducedWord.prod φ
        (unitsSMulWithCancel φ 1 (cons g✝ { val := -↑1, inv := -↑1⁻¹, val_inv := ⋯, inv_val := ⋯ } w✝ h1✝ h2✝)
            hcan).toReducedWord =
      t ^ ↑1 *
        ReducedWord.prod φ (cons g✝ { val := -↑1, inv := -↑1⁻¹, val_inv := ⋯, inv_val := ⋯ } w✝ h1✝ h2✝).toReducedWord
⊢ of ↑((toSubgroupEquiv φ 1) ⟨g✝, ⋯⟩) * ReducedWord.prod φ w✝.toReducedWord =
    t ^ ↑1 * (of g✝ * ((t ^ ↑1)⁻¹ * ReducedWord.prod φ w✝.toReducedWord))

Tactic:
simp [equiv_eq_conj, mul_assoc]

Goal state after:
Module: Mathlib.GroupTheory.Perm.Cycle.PossibleTypes

Goal state before:
pp: case mpr
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
m : Multiset ℕ
⊢ (m.sum ≤ Fintype.card α ∧ ∀ a ∈ m, 2 ≤ a) → ∃ g, g.cycleType = m

Tactic:
rintro ⟨hc, h2c⟩
    have hc' : m.toList.sum ≤ Fintype.card α := by
      simp only [Multiset.sum_toList]
      exact hc
    obtain ⟨p, hp_length, hp_nodup, hp_disj⟩ := List.exists_pw_disjoint_with_card hc'
    use List.prod (List.map (fun l => List.formPerm l) p)
    have hp2 : ∀ x ∈ p, 2 ≤ x.length := by
      intro x hx
      apply h2c x.length
      rw [← Multiset.mem_toList, ← hp_length, List.mem_map]
      exact ⟨x, hx, rfl⟩
    rw [Equiv.Perm.cycleType_eq _ rfl]
    · -- lengths
      rw [← Multiset.coe_toList m]
      apply congr_arg
      rw [List.map_map]; rw [← hp_length]
      apply List.map_congr_left
      intro x hx; simp only [Function.comp_apply]
      rw [List.support_formPerm_of_nodup x (hp_nodup x hx)]
      · -- length
        rw [List.toFinset_card_of_nodup (hp_nodup x hx)]
      · -- length >= 1
        grind
    · -- cycles
      simpa using fun a b ↦ List.isCycle_formPerm (hp_nodup a b) (hp2 a b)
    · -- disjoint
      rw [List.pairwise_map]
      apply List.Pairwise.imp_of_mem _ hp_disj
      intro a b ha hb hab
      rw [List.formPerm_disjoint_iff (hp_nodup a ha) (hp_nodup b hb) (hp2 a ha) (hp2 b hb)]
      exact hab

Goal state after:
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 : (ConjAct.toConjAct k • g).cycleFactorsFinset = ConjAct.toConjAct k • g.cycleFactorsFinset
⊢ ↑g.cycleFactorsFinset = ConjAct.toConjAct k • ↑g.cycleFactorsFinset

Tactic:
ConjAct.toConjAct_smul,

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 : (k * g * k⁻¹).cycleFactorsFinset = ConjAct.toConjAct k • g.cycleFactorsFinset
⊢ ↑g.cycleFactorsFinset = ConjAct.toConjAct k • ↑g.cycleFactorsFinset
Module: Mathlib.GroupTheory.Perm.Centralizer

Goal state before:
pp: α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g : Perm α
a✝ b✝ : Perm ↥g.cycleFactorsFinset
hσ : ∀ (a : Perm α) (b : a ∈ g.cycleFactorsFinset), #(↑(a✝ ⟨a, b⟩)).support = #a.support
hτ : ∀ (a : Perm α) (b : a ∈ g.cycleFactorsFinset), #(↑(b✝ ⟨a, b⟩)).support = #a.support
c : Perm α
hc : c ∈ g.cycleFactorsFinset
⊢ #(↑(b✝ ⟨c, hc⟩)).support = #c.support

Tactic:
hτ

Goal state after:
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g : Perm α
a✝ b✝ : Perm ↥g.cycleFactorsFinset
hσ : ∀ (a : Perm α) (b : a ∈ g.cycleFactorsFinset), #(↑(a✝ ⟨a, b⟩)).support = #a.support
hτ : ∀ (a : Perm α) (b : a ∈ g.cycleFactorsFinset), #(↑(b✝ ⟨a, b⟩)).support = #a.support
c : Perm α
hc : c ∈ g.cycleFactorsFinset
⊢ #c.support = #c.support
Module: Mathlib.GroupTheory.Perm.Centralizer

Goal state before:
pp: α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g : Perm α
a : g.Basis
τ : ↥(range_toPermHom' g)
x : α
c : ↥g.cycleFactorsFinset
hx : x ∈ (↑c).support
m : ℤ
hm : (g ^ m) (a c) = x
hx' : ↑c = g.cycleOf x
hx'' : g.cycleOf x ∈ g.cycleFactorsFinset
n : ℕ := Nat.find ⋯
hn : (g ^ ↑n) (a c) = x
this : a.ofPermHomFun τ x = (g ^ ↑n) (a (↑τ c))
⊢ ↑n ≡ m [ZMOD ↑(#(↑c).support)]

Tactic:
rw [← IsCycleOn.zpow_apply_eq_zpow_apply
      (isCycleOn_support_of_mem_cycleFactorsFinset c.prop) (mem_support_self a c)]

Goal state after:
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g : Perm α
a : g.Basis
τ : ↥(range_toPermHom' g)
x : α
c : ↥g.cycleFactorsFinset
hx : x ∈ (↑c).support
m : ℤ
hm : (g ^ m) (a c) = x
hx' : ↑c = g.cycleOf x
hx'' : g.cycleOf x ∈ g.cycleFactorsFinset
n : ℕ := Nat.find ⋯
hn : (g ^ ↑n) (a c) = x
this : a.ofPermHomFun τ x = (g ^ ↑n) (a (↑τ c))
⊢ (g ^ ↑n) (a c) = (g ^ m) (a c)
Module: Mathlib.GroupTheory.PushoutI

Goal state before:
pp: ι : Type u_1
G : ι → Type u_2
H : Type u_3
inst✝¹ : (i : ι) → Monoid (G i)
inst✝ : Monoid H
φ : (i : ι) → H →* G i
i : ι
g : G i
⊢ ofCoprodI (CoprodI.of g) = (of i) g

Tactic:
simp [ofCoprodI]

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

Goal state before:
pp: case refine_1.hind
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g : Perm α
a b : ↥g.cycleFactorsFinset
h : ¬b = a
⊢ (↑a).Disjoint ↑b

Tactic:
apply cycleFactorsFinset_pairwise_disjoint g a.2 b.2

Goal state after:
case refine_1.hind
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g : Perm α
a b : ↥g.cycleFactorsFinset
h : ¬b = a
⊢ ↑a ≠ ↑b
Module: Mathlib.GroupTheory.SpecificGroups.Alternating.Centralizer

Goal state before:
pp: α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
g : Perm α
h : Subgroup.centralizer {g} ≤ alternatingGroup α
hm : 2 + g.cycleType.sum ≤ Fintype.card α
⊢ 1 < Fintype.card α - g.cycleType.sum

Tactic:
Nat.lt_iff_add_one_le,

Goal state after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
g : Perm α
h : Subgroup.centralizer {g} ≤ alternatingGroup α
hm : 2 + g.cycleType.sum ≤ Fintype.card α
⊢ 1 + 1 ≤ Fintype.card α - g.cycleType.sum
Module: Mathlib.GroupTheory.Perm.Centralizer

Goal state before:
pp: case pos.H1
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)!

Tactic:
have : 0 < m.prod := Multiset.prod_pos <| fun a ha => zero_lt_two.trans_le (hm.2 a ha)

Goal state after:
case pos.H1
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
m : Multiset ℕ
hm : m.sum ≤ Fintype.card α ∧ ∀ a ∈ m, 2 ≤ a
this : 0 < m.prod
⊢ 0 < (Fintype.card α - m.sum)! * m.prod * ∏ n ∈ m.toFinset, (Multiset.count n m)!