mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Geometry.Manifold.WhitneyEmbedding

Goal state before:
pp: case convert_2
ι : Type uι
E : Type uE
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
inst✝⁶ : FiniteDimensional ℝ E
H : Type uH
inst✝⁵ : TopologicalSpace H
I : ModelWithCorners ℝ E H
M : Type uM
inst✝⁴ : TopologicalSpace M
inst✝³ : ChartedSpace H M
inst✝² : IsManifold I ∞ M
inst✝¹ : T2Space M
inst✝ : Fintype ι
s : Set M
f : SmoothBumpCovering ι I M s
x : M
hx : x ∈ s
L : (ι → E × ℝ) →L[ℝ] E := ContinuousLinearMap.fst ℝ E ℝ ∘SL ContinuousLinearMap.proj (f.ind x hx)
this : HasMFDerivAt% (⇑L ∘ ⇑f.embeddingPiTangent) x (L ∘SL mfderiv% ⇑f.embeddingPiTangent x)
y : M
hy : ↑(f.toFun (f.ind x hx)) y = 1 y
⊢ ↑(f.toFun (f.ind x hx)) y • ↑(extChartAt I (f.c (f.ind x hx))) y = ↑(extChartAt I (f.c (f.ind x hx))) y

Tactic:
rw [hy, Pi.one_apply, one_smul]

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

Goal state before:
pp: n : ℕ
⊢ ∀ (a b c : DihedralGroup n), a * b * c = a * (b * c)

Tactic:
rintro (a | a) (b | b) (c | c) <;> simp only [(· * ·), mul]

Goal state after:
case r.r.r
n : ℕ
a b c : ZMod n
⊢ r (a + b + c) = r (a + (b + c))

case r.r.sr
n : ℕ
a b c : ZMod n
⊢ sr (c - (a + b)) = sr (c - b - a)

case r.sr.r
n : ℕ
a b c : ZMod n
⊢ sr (b - a + c) = sr (b + c - a)

case r.sr.sr
n : ℕ
a b c : ZMod n
⊢ r (c - (b - a)) = r (a + (c - b))

case sr.r.r
n : ℕ
a b c : ZMod n
⊢ sr (a + b + c) = sr (a + (b + c))

case sr.r.sr
n : ℕ
a b c : ZMod n
⊢ r (c - (a + b)) = r (c - b - a)

case sr.sr.r
n : ℕ
a b c : ZMod n
⊢ r (b - a + c) = r (b + c - a)

case sr.sr.sr
n : ℕ
a b c : ZMod n
⊢ sr (c - (b - a)) = sr (a + (c - b))
Module: Mathlib.GroupTheory.SpecificGroups.Dihedral

Goal state before:
pp: case r
n : ℕ
a : ZMod n
⊢ (r a).inv * r a = 1

Tactic:
exact congr_arg r (neg_add_cancel a)

Goal state after:
Module: Mathlib.GroupTheory.CommutingProbability

Goal state before:
pp: case pos
G : Type u_2
inst✝ : Group G
h : ↑(Nat.card G) = 0
⊢ ↑(Nat.card (ConjClasses G)) * ↑(Nat.card G) / (↑(Nat.card G) * ↑(Nat.card G)) =
    ↑(Nat.card (ConjClasses G)) / ↑(Nat.card G)

Tactic:
h,

Goal state after:
case pos
G : Type u_2
inst✝ : Group G
h : ↑(Nat.card G) = 0
⊢ ↑(Nat.card (ConjClasses G)) * 0 / (0 * 0) = ↑(Nat.card (ConjClasses G)) / 0
Module: Mathlib.GroupTheory.SpecificGroups.Dihedral

Goal state before:
pp: n : ℕ
hn : Odd n
u : (ZMod n)ˣ := ZMod.unitOfCoprime 2 ⋯
hu : ∀ (a : ZMod n), a + a = 0 ↔ a = 0
i j : ZMod n
h✝ : Commute (sr i, sr j).1 (sr i, sr j).2
h : i = j
⊢ ↑u⁻¹ * (i + j) = i ∧ ↑u⁻¹ * (i + j) = j

Tactic:
h,

Goal state after:
n : ℕ
hn : Odd n
u : (ZMod n)ˣ := ZMod.unitOfCoprime 2 ⋯
hu : ∀ (a : ZMod n), a + a = 0 ↔ a = 0
i j : ZMod n
h✝ : Commute (sr i, sr j).1 (sr i, sr j).2
h : i = j
⊢ ↑u⁻¹ * (j + j) = j ∧ ↑u⁻¹ * (j + j) = j
Module: Mathlib.GroupTheory.CoprodI

Goal state before:
pp: case neg
ι : Type u_1
M : ι → Type u_2
inst✝¹ : (i : ι) → Monoid (M i)
inst✝ : (i : ι) → DecidableEq (M i)
i : ι
m : M i
w : Word M
h : w.fstIdx ≠ some i
m' : M i
w' : Word M
h' : w'.fstIdx ≠ some i
he : rcons { head := m, tail := w, fstIdx_ne := h } = rcons { head := m', tail := w', fstIdx_ne := h' }
hm : m = 1
hm' : ¬m' = 1
⊢ False

Tactic:
simp only [rcons, dif_pos hm, dif_neg hm'] at he

Goal state after:
case neg
ι : Type u_1
M : ι → Type u_2
inst✝¹ : (i : ι) → Monoid (M i)
inst✝ : (i : ι) → DecidableEq (M i)
i : ι
m : M i
w : Word M
h : w.fstIdx ≠ some i
m' : M i
w' : Word M
h' : w'.fstIdx ≠ some i
hm : m = 1
hm' : ¬m' = 1
he : w = cons m' w' ⋯ ⋯
⊢ False
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: case h
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i : B
ω' : List B
h : cs.IsReduced (i :: ω')
hw : cs.wordProd (i :: ω') ≠ 1
h₁ : i :: ω' ≠ []
⊢ cs.length (cs.simple i * cs.wordProd (i :: ω')) < cs.length (cs.wordProd (i :: ω'))

Tactic:
h,

Goal state after:
case h
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i : B
ω' : List B
h : cs.IsReduced (i :: ω')
hw : cs.wordProd (i :: ω') ≠ 1
h₁ : i :: ω' ≠ []
⊢ cs.length (cs.simple i * cs.wordProd (i :: ω')) < (i :: ω').length
Module: Mathlib.GroupTheory.CoprodI

Goal state before:
pp: ι : Type u_1
M : ι → Type u_2
inst✝ : (i : ι) → Monoid (M i)
i j : ι
w : NeWord M i j
x : M i
hnotone : x * w.head ≠ 1
⊢ (w.mulHead x hnotone).head = x * w.head

Tactic:
by
  induction w
  · rfl
  · simp [*, mulHead]

Goal state after:
Module: Mathlib.GroupTheory.DivisibleHull

Goal state before:
pp: M : Type u_1
inst✝ : AddCommMonoid M
a : ℚ≥0
m : M
s : ℕ+
⊢ a • mk m s = mk (a.num • m) (⟨a.den, ⋯⟩ * s)

Tactic:
by
  convert! LocalizedModule.mk'_smul_mk ℚ≥0 a.num m ⟨a.den, by simp⟩ (↑ⁿ s)
  simp [IsLocalization.eq_mk'_iff_mul_eq]

Goal state after:
Module: Mathlib.GroupTheory.DivisibleHull

Goal state before:
pp: case e'_1.e'_3
M : Type u_2
inst✝² : AddCommMonoid M
inst✝¹ : LinearOrder M
inst✝ : IsOrderedCancelAddMonoid M
m n m' n' : M
s t s' t' : ℕ+
h : ↑s' • m = ↑s • m'
h' : ↑t' • n = ↑t • n'
⊢ ↑t' • ↑t • ↑s' • m = ↑s • ↑t • ↑t' • m'

Tactic:
h,

Goal state after:
case e'_1.e'_3
M : Type u_2
inst✝² : AddCommMonoid M
inst✝¹ : LinearOrder M
inst✝ : IsOrderedCancelAddMonoid M
m n m' n' : M
s t s' t' : ℕ+
h : ↑s' • m = ↑s • m'
h' : ↑t' • n = ↑t • n'
⊢ ↑t' • ↑t • ↑s • m' = ↑s • ↑t • ↑t' • m'
Module: Mathlib.GroupTheory.DoubleCoset

Goal state before:
pp: G : Type u_1
inst✝ : Group G
H K : Subgroup G
a x : G
⊢ x ∈ ⋃ h, (↑h * a) • ↑K ↔ x ∈ doubleCoset a ↑H ↑K

Tactic:
simp only [mem_leftCoset_iff, mul_inv_rev, Set.mem_iUnion, mem_doubleCoset]

Goal state after:
G : Type u_1
inst✝ : Group G
H K : Subgroup G
a x : G
⊢ (∃ i, a⁻¹ * (↑i)⁻¹ * x ∈ ↑K) ↔ ∃ x_1 ∈ ↑H, ∃ y ∈ ↑K, x = x_1 * a * y
Module: Mathlib.GroupTheory.FiniteAbelian.Duality

Goal state before:
pp: G : Type u_1
M : Type u_2
inst✝² : CommGroup G
inst✝¹ : Finite G
inst✝ : CommMonoid M
H : ∀ (n : ℕ), n ∣ Monoid.exponent G → ∀ (a : ZMod n), a ≠ 0 → ∃ φ, φ (Multiplicative.ofAdd a) ≠ 1
a : G
ha : a ≠ 1
ι : Type
w✝ : Fintype ι
n : ι → ℕ
left✝ : ∀ (i : ι), 1 < n i
h : Nonempty (G ≃* ((i : ι) → Multiplicative (ZMod (n i))))
e : G ≃* ((i : ι) → Multiplicative (ZMod (n i))) := h.some
⊢ ∃ i, e a i ≠ 1

Tactic:
contrapose! ha

Goal state after:
G : Type u_1
M : Type u_2
inst✝² : CommGroup G
inst✝¹ : Finite G
inst✝ : CommMonoid M
H : ∀ (n : ℕ), n ∣ Monoid.exponent G → ∀ (a : ZMod n), a ≠ 0 → ∃ φ, φ (Multiplicative.ofAdd a) ≠ 1
a : G
ι : Type
w✝ : Fintype ι
n : ι → ℕ
left✝ : ∀ (i : ι), 1 < n i
h : Nonempty (G ≃* ((i : ι) → Multiplicative (ZMod (n i))))
e : G ≃* ((i : ι) → Multiplicative (ZMod (n i))) := h.some
ha : ∀ (i : ι), e a i = 1
⊢ a = 1
Module: Mathlib.GroupTheory.DivisibleHull

Goal state before:
pp: case h₂
M✝ : Type u_1
inst✝³ : AddCommMonoid M✝
M : Type u_2
inst✝² : AddCommGroup M
inst✝¹ : LinearOrder M
inst✝ : IsOrderedAddMonoid M
⊢ (archimedeanClassOrderHomInv M).comp (archimedeanClassOrderHom M) = OrderHom.id

Tactic:
· ext a
    induction a with | mk _
    simp [archimedeanClassOrderHom, archimedeanClassOrderHomInv]

Goal state after:
Module: Mathlib.GroupTheory.FiniteAbelian.Duality

Goal state before:
pp: G : Type u_1
M : Type u_2
inst✝² : CommGroup G
inst✝¹ : Finite G
inst✝ : CommMonoid M
hM : HasEnoughRootsOfUnity M (Monoid.exponent G)
Φ : Subgroup (G →* Mˣ)
g : G
⊢ g ∈ (subgroupOrderIsoSubgroupMonoidHom G M).symm (OrderDual.toDual Φ) ↔ ∀ φ ∈ Φ, φ g = 1

Tactic:
subgroupOrderIsoSubgroupMonoidHom,

Goal state after:
G : Type u_1
M : Type u_2
inst✝² : CommGroup G
inst✝¹ : Finite G
inst✝ : CommMonoid M
hM : HasEnoughRootsOfUnity M (Monoid.exponent G)
Φ : Subgroup (G →* Mˣ)
g : G
⊢ g ∈
      (OrderIso.symm
          { toFun := fun H ↦ OrderDual.toDual (domRestrictHom H Mˣ).ker,
            invFun := fun Φ ↦ (monoidHomMonoidHomEquiv G M).mapSubgroup (domRestrictHom (OrderDual.ofDual Φ) Mˣ).ker,
            left_inv := ⋯, right_inv := ⋯, map_rel_iff' := ⋯ })
        (OrderDual.toDual Φ) ↔
    ∀ φ ∈ Φ, φ g = 1
Module: Mathlib.GroupTheory.Schreier

Goal state before:
pp: case refine_3
G : Type u_1
inst✝ : Group G
H : Subgroup G
R S : Set G
hR : IsComplement (↑H) R
hR1 : 1 ∈ R
hS : closure S = ⊤
f : G → ↑R := hR.toRightFun
U : Set G := (fun g ↦ g * (↑(f g))⁻¹) '' (R * S)
g : G
x✝ : g ∈ ⊤
s : G
hs : s ∈ S
u : G
hu : u ∈ ↑(closure U)
r : G
hr : r ∈ R
⊢ (fun g ↦ g * (↑(f g))⁻¹) (↑(f (r * s⁻¹)) * s) = ↑(f (r * s⁻¹)) * s * r⁻¹

Tactic:
mul_right_inj,

Goal state after:
case refine_3
G : Type u_1
inst✝ : Group G
H : Subgroup G
R S : Set G
hR : IsComplement (↑H) R
hR1 : 1 ∈ R
hS : closure S = ⊤
f : G → ↑R := hR.toRightFun
U : Set G := (fun g ↦ g * (↑(f g))⁻¹) '' (R * S)
g : G
x✝ : g ∈ ⊤
s : G
hs : s ∈ S
u : G
hu : u ∈ ↑(closure U)
r : G
hr : r ∈ R
⊢ (↑(f (↑(f (r * s⁻¹)) * s)))⁻¹ = r⁻¹
Module: Mathlib.GroupTheory.Transfer

Goal state before:
pp: G : Type u_1
inst✝³ : Group G
H : Subgroup G
A : Type u_2
inst✝² : CommGroup A
ϕ : ↥H →* A
inst✝¹ : H.FiniteIndex
g : G
inst✝ : Fintype (Quotient (orbitRel (↥(zpowers g)) (G ⧸ H)))
this : Fintype (G ⧸ H) := fintypeQuotientOfFiniteIndex
q : orbitRel.Quotient (↥(zpowers g)) (G ⧸ H)
⊢ ∀ (x : ZMod (Function.minimalPeriod (fun x ↦ g • x) (Quotient.out q))),
    x ≠ 0 →
      ϕ
          ⟨(g ^ x.cast * Quotient.out (Quotient.out q))⁻¹ *
              if x = 0 then g ^ Function.minimalPeriod (fun x ↦ g • x) (Quotient.out q) * Quotient.out (Quotient.out q)
              else g ^ x.cast * Quotient.out (Quotient.out q),
            ⋯⟩ =
        1

Tactic:
intro k

Goal state after:
G : Type u_1
inst✝³ : Group G
H : Subgroup G
A : Type u_2
inst✝² : CommGroup A
ϕ : ↥H →* A
inst✝¹ : H.FiniteIndex
g : G
inst✝ : Fintype (Quotient (orbitRel (↥(zpowers g)) (G ⧸ H)))
this : Fintype (G ⧸ H) := fintypeQuotientOfFiniteIndex
q : orbitRel.Quotient (↥(zpowers g)) (G ⧸ H)
k : ZMod (Function.minimalPeriod (fun x ↦ g • x) (Quotient.out q))
⊢ k ≠ 0 →
    ϕ
        ⟨(g ^ k.cast * Quotient.out (Quotient.out q))⁻¹ *
            if k = 0 then g ^ Function.minimalPeriod (fun x ↦ g • x) (Quotient.out q) * Quotient.out (Quotient.out q)
            else g ^ k.cast * Quotient.out (Quotient.out q),
          ⋯⟩ =
      1
Module: Mathlib.GroupTheory.Transfer

Goal state before:
pp: case pos
G : Type u_1
inst✝ : Group G
H : Subgroup G
g : G
key : ∀ (k : ℕ) (g₀ : G), g₀⁻¹ * g ^ k * g₀ ∈ H → g₀⁻¹ * g ^ k * g₀ = g ^ k
hH : H.index = 0
⊢ g ^ H.index ∈ H

Tactic:
hH,

Goal state after:
case pos
G : Type u_1
inst✝ : Group G
H : Subgroup G
g : G
key : ∀ (k : ℕ) (g₀ : G), g₀⁻¹ * g ^ k * g₀ ∈ H → g₀⁻¹ * g ^ k * g₀ = g ^ k
hH : H.index = 0
⊢ g ^ 0 ∈ H
Module: Mathlib.GroupTheory.Schreier

Goal state before:
pp: G : Type u_1
inst✝¹ : Group G
inst✝ : Finite ↑(commutatorSet G)
⊢ Nat.card ↥(_root_.commutator G) ≤ cardCommutatorBound (Nat.card ↑(commutatorSet G))

Tactic:
have h1 := index_center_le_pow (closureCommutatorRepresentatives G)
  have h2 := card_commutator_dvd_index_center_pow (closureCommutatorRepresentatives G)
  rw [card_commutatorSet_closureCommutatorRepresentatives] at h1 h2
  rw [card_commutator_closureCommutatorRepresentatives] at h2
  replace h1 :=
    h1.trans
      (Nat.pow_le_pow_right Finite.card_pos (rank_closureCommutatorRepresentatives_le G))
  replace h2 := h2.trans (pow_dvd_pow _ (add_le_add_left (mul_le_mul_left h1 _) 1))
  rw [← pow_succ] at h2
  refine (Nat.le_of_dvd ?_ h2).trans (Nat.pow_le_pow_left h1 _)
  exact pow_pos (Nat.pos_of_ne_zero FiniteIndex.index_ne_zero) _

Goal state after:
Module: Mathlib.GroupTheory.Schreier

Goal state before:
pp: G : Type u_1
inst✝¹ : Group G
H : Subgroup G
R S : Set G
inst✝ : Finite ↑(commutatorSet G)
h2 :
  Nat.card ↥(_root_.commutator G) ∣
    (center ↥(closureCommutatorRepresentatives G)).index ^
      ((center ↥(closureCommutatorRepresentatives G)).index *
          Nat.card ↑(commutatorSet ↥(closureCommutatorRepresentatives G)) +
        1)
h : Nat.card ↥(_root_.commutator G) = 0
⊢ False

Tactic:
h,

Goal state after:
G : Type u_1
inst✝¹ : Group G
H : Subgroup G
R S : Set G
inst✝ : Finite ↑(commutatorSet G)
h2 :
  0 ∣
    (center ↥(closureCommutatorRepresentatives G)).index ^
      ((center ↥(closureCommutatorRepresentatives G)).index *
          Nat.card ↑(commutatorSet ↥(closureCommutatorRepresentatives G)) +
        1)
h : Nat.card ↥(_root_.commutator G) = 0
⊢ False
Module: Mathlib.Order.Radical

Goal state before:
pp: case inr
α : Type u_1
inst✝¹ : CompleteLattice α
inst✝ : IsCoatomic α
a : α
h : a ⊔ radical α = ⊤
m : α
c : IsCoatom m
le : a ≤ m
q : a ⊔ radical α ≤ m
⊢ a = ⊤

Tactic:
h,

Goal state after:
case inr
α : Type u_1
inst✝¹ : CompleteLattice α
inst✝ : IsCoatomic α
a : α
h : a ⊔ radical α = ⊤
m : α
c : IsCoatom m
le : a ≤ m
q : ⊤ ≤ m
⊢ a = ⊤
Module: Mathlib.GroupTheory.Nilpotent

Goal state before:
pp: G : Type u_1
inst✝ : Group G
H : ℕ → Subgroup G
n : ℕ
hn : H n = ⊤
hasc : IsAscendingCentralSeries H
⊢ IsDescendingCentralSeries fun m ↦ H (n - m)

Tactic:
obtain ⟨h0, hH⟩ := hasc

Goal state after:
G : Type u_1
inst✝ : Group G
H : ℕ → Subgroup G
n : ℕ
hn : H n = ⊤
h0 : H 0 = ⊥
hH : ∀ (x : G) (n : ℕ), x ∈ H (n + 1) → ∀ (g : G), ⁅x, g⁆ ∈ H n
⊢ IsDescendingCentralSeries fun m ↦ H (n - m)
Module: Mathlib.GroupTheory.FreeGroup.Orbit

Goal state before:
pp: α : Type u_1
X : Type u_2
inst✝¹ : DecidableEq α
inst✝ : MulAction (FreeGroup α) X
x : X
w : α × Bool
g : FreeGroup α
hg : g ∈ startsWith w
l : List (α × Bool) := g.toWord
h : ⟨g, hg⟩ = ⟨mk g.toWord, ⋯⟩
a : α × Bool
hl : [a] = g.toWord
⊢ (mk [w])⁻¹ • ⟨g, hg⟩ • x ∈ (⋃ v ∈ {z | z ≠ (w.1, !w.2)}, MulAction.orbit (↑(startsWith v)) x) ∪ {x}

Tactic:
h,

Goal state after:
α : Type u_1
X : Type u_2
inst✝¹ : DecidableEq α
inst✝ : MulAction (FreeGroup α) X
x : X
w : α × Bool
g : FreeGroup α
hg : g ∈ startsWith w
l : List (α × Bool) := g.toWord
h : ⟨g, hg⟩ = ⟨mk g.toWord, ⋯⟩
a : α × Bool
hl : [a] = g.toWord
⊢ (mk [w])⁻¹ • ⟨mk g.toWord, ⋯⟩ • x ∈ (⋃ v ∈ {z | z ≠ (w.1, !w.2)}, MulAction.orbit (↑(startsWith v)) x) ∪ {x}
Module: Mathlib.GroupTheory.Nilpotent

Goal state before:
pp: case refine_2
G : Type u_1
inst✝ : Group G
hG : Group.IsNilpotent G
⊢ ∀ (n : ℕ), (∃ H, IsAscendingCentralSeries H ∧ H n = ⊤) → upperCentralSeries G n = ⊤

Tactic:
rintro n ⟨H, ⟨hH, hn⟩⟩

Goal state after:
case refine_2
G : Type u_1
inst✝ : Group G
hG : Group.IsNilpotent G
n : ℕ
H : ℕ → Subgroup G
hH : IsAscendingCentralSeries H
hn : H n = ⊤
⊢ upperCentralSeries G n = ⊤
Module: Mathlib.GroupTheory.Nilpotent

Goal state before:
pp: case refine_1
G : Type u_1
inst✝ : Group G
hG : Group.IsNilpotent G
⊢ ∀ (n : ℕ), (∃ H, IsAscendingCentralSeries H ∧ H n = ⊤) → ∃ H, IsDescendingCentralSeries H ∧ H n = ⊥

Tactic:
rintro n ⟨H, ⟨hH, hn⟩⟩

Goal state after:
case refine_1
G : Type u_1
inst✝ : Group G
hG : Group.IsNilpotent G
n : ℕ
H : ℕ → Subgroup G
hH : IsAscendingCentralSeries H
hn : H n = ⊤
⊢ ∃ H, IsDescendingCentralSeries H ∧ H n = ⊥
Module: Mathlib.GroupTheory.Nilpotent

Goal state before:
pp: case refine_2
G : Type u_1
inst✝ : Group G
hG : Group.IsNilpotent G
⊢ ∀ (n : ℕ), (∃ H, IsDescendingCentralSeries H ∧ H n = ⊥) → ∃ H, IsAscendingCentralSeries H ∧ H n = ⊤

Tactic:
rintro n ⟨H, ⟨hH, hn⟩⟩

Goal state after:
case refine_2
G : Type u_1
inst✝ : Group G
hG : Group.IsNilpotent G
n : ℕ
H : ℕ → Subgroup G
hH : IsDescendingCentralSeries H
hn : H n = ⊥
⊢ ∃ H, IsAscendingCentralSeries H ∧ H n = ⊤
Module: Mathlib.GroupTheory.FreeGroup.Orbit

Goal state before:
pp: α : Type u_1
X : Type u_2
inst✝¹ : DecidableEq α
inst✝ : MulAction (FreeGroup α) X
x : X
w : α × Bool
g : FreeGroup α
hg : g ∈ startsWith w
l✝ : List (α × Bool) := g.toWord
h : ⟨g, hg⟩ = ⟨mk g.toWord, ⋯⟩
a b : α × Bool
l : List (α × Bool)
hl : a :: b :: l = g.toWord
ha : a = w
h1 : (a.1 = b.1 → a.2 = b.2) ∧ IsReduced (b :: l)
⊢ (mk [w])⁻¹ • ⟨g, hg⟩ • x ∈ MulAction.orbit (↑(startsWith b)) x

Tactic:
h,

Goal state after:
α : Type u_1
X : Type u_2
inst✝¹ : DecidableEq α
inst✝ : MulAction (FreeGroup α) X
x : X
w : α × Bool
g : FreeGroup α
hg : g ∈ startsWith w
l✝ : List (α × Bool) := g.toWord
h : ⟨g, hg⟩ = ⟨mk g.toWord, ⋯⟩
a b : α × Bool
l : List (α × Bool)
hl : a :: b :: l = g.toWord
ha : a = w
h1 : (a.1 = b.1 → a.2 = b.2) ∧ IsReduced (b :: l)
⊢ (mk [w])⁻¹ • ⟨mk g.toWord, ⋯⟩ • x ∈ MulAction.orbit (↑(startsWith b)) x
Module: Mathlib.GroupTheory.Nilpotent

Goal state before:
pp: case refine_1
G : Type u_1
inst✝ : Group G
hG : Group.IsNilpotent G
⊢ ∀ (n : ℕ), (∃ H, IsDescendingCentralSeries H ∧ H n = ⊥) → ⊤.lowerCentralSeries n = ⊥

Tactic:
rintro n ⟨H, ⟨hH, hn⟩⟩

Goal state after:
case refine_1
G : Type u_1
inst✝ : Group G
hG : Group.IsNilpotent G
n : ℕ
H : ℕ → Subgroup G
hH : IsDescendingCentralSeries H
hn : H n = ⊥
⊢ ⊤.lowerCentralSeries n = ⊥
Module: Mathlib.GroupTheory.Goursat

Goal state before:
pp: G : Type u_1
H : Type u_2
inst✝¹ : Group G
inst✝ : Group H
I : Subgroup (G × H)
G' : Subgroup G := map (MonoidHom.fst G H) I
H' : Subgroup H := map (MonoidHom.snd G H) I
P : ↥I →* ↥G' := (MonoidHom.fst G H).subgroupMap I
Q : ↥I →* ↥H' := (MonoidHom.snd G H).subgroupMap I
I' : Subgroup (↥G' × ↥H') := (P.prod Q).range
hI₁' : Surjective (Prod.fst ∘ ⇑I'.subtype)
hI₂' : Surjective (Prod.snd ∘ ⇑I'.subtype)
this✝ : I'.goursatFst.Normal
this : I'.goursatSnd.Normal
e : ↥G' ⧸ I'.goursatFst ≃* ↥H' ⧸ I'.goursatSnd
he :
  (((QuotientGroup.mk' I'.goursatFst).prodMap (QuotientGroup.mk' I'.goursatSnd)).comp I'.subtype).range =
    e.toMonoidHom.graph
⊢ ((QuotientGroup.mk' (P.prod Q).range.goursatFst).prodMap (QuotientGroup.mk' (P.prod Q).range.goursatSnd)).ker ≤
    (P.prod Q).range

Tactic:
convert! goursatFst_prod_goursatSnd_le (P.prod Q).range
    ext ⟨g, h⟩
    simp_rw [G', H', MonoidHom.mem_ker, MonoidHom.coe_prodMap, Prod.map_apply, Subgroup.mem_prod,
      Prod.one_eq_mk, Prod.ext_iff, ← MonoidHom.mem_ker, QuotientGroup.ker_mk']

Goal state after:
Module: Mathlib.GroupTheory.Nilpotent

Goal state before:
pp: η : Type u_2
Gs : η → Type u_3
inst✝² : (i : η) → Group (Gs i)
inst✝¹ : Fintype η
inst✝ : ∀ (i : η), IsNilpotent (Gs i)
⊢ ∀ (c : ℕ), nilpotencyClass ((i : η) → Gs i) ≤ c ↔ (Finset.univ.sup fun i ↦ nilpotencyClass (Gs i)) ≤ c

Tactic:
intro k

Goal state after:
η : Type u_2
Gs : η → Type u_3
inst✝² : (i : η) → Group (Gs i)
inst✝¹ : Fintype η
inst✝ : ∀ (i : η), IsNilpotent (Gs i)
k : ℕ
⊢ nilpotencyClass ((i : η) → Gs i) ≤ k ↔ (Finset.univ.sup fun i ↦ nilpotencyClass (Gs i)) ≤ k
Module: Mathlib.GroupTheory.GroupAction.Blocks

Goal state before:
pp: case inr
M : Type u_3
α : Type u_4
inst✝¹ : Group M
inst✝ : MulAction M α
B : Set α
g : M
h : B = univ
⊢ g • B = univ

Tactic:
h,

Goal state after:
case inr
M : Type u_3
α : Type u_4
inst✝¹ : Group M
inst✝ : MulAction M α
B : Set α
g : M
h : B = univ
⊢ g • univ = univ
Module: Mathlib.GroupTheory.GroupAction.Blocks

Goal state before:
pp: M : Type u_3
α : Type u_4
inst✝¹ : Group M
inst✝ : MulAction M α
B : Set α
g : M
⊢ IsTrivialBlock (g • B) ↔ IsTrivialBlock B

Tactic:
constructor
  · intro H
    convert! IsTrivialBlock.smul H g⁻¹
    simp only [inv_smul_smul]
  · intro H
    exact IsTrivialBlock.smul H g

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

Goal state before:
pp: α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g k : Perm α
⊢ (ConjAct.toConjAct k • g).cycleFactorsFinset = Finset.map (MulAut.conj k).toEmbedding g.cycleFactorsFinset

Tactic:
by
  ext c
  rw [ConjAct.smul_def, ConjAct.ofConjAct_toConjAct, Finset.mem_map_equiv,
    ← mem_cycleFactorsFinset_conj g k]
  -- We avoid `group` here to minimize imports while low in the hierarchy;
  -- typically it would be better to invoke the tactic.
  simp [mul_assoc]

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

Goal state before:
pp: case inl
G : Type u_1
inst✝³ : Group G
X : Type u_2
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
B : Set X
inst✝ : Finite X
hB : IsBlock G B
hB' : Nat.card X < 2 * (orbit G B).ncard
h : B = ∅
⊢ B.ncard < 2

Tactic:
h,

Goal state after:
case inl
G : Type u_1
inst✝³ : Group G
X : Type u_2
inst✝² : MulAction G X
inst✝¹ : IsPretransitive G X
B : Set X
inst✝ : Finite X
hB : IsBlock G B
hB' : Nat.card X < 2 * (orbit G B).ncard
h : B = ∅
⊢ ∅.ncard < 2
Module: Mathlib.GroupTheory.GroupAction.Blocks

Goal state before:
pp: G : Type u_1
inst✝² : Group G
X : Type u_2
inst✝¹ : MulAction G X
inst✝ : IsPretransitive G X
B : Set X
a : X
hfB : B.Finite
B' : Set X := ⋂ k, ⋂ (_ : a ∈ k • B), k • B
hfB_ne : B.Nonempty
⊢ ∀ (k : G), a ∈ k • B → B' ⊆ k • B

Tactic:
intro k

Goal state after:
G : Type u_1
inst✝² : Group G
X : Type u_2
inst✝¹ : MulAction G X
inst✝ : IsPretransitive G X
B : Set X
a : X
hfB : B.Finite
B' : Set X := ⋂ k, ⋂ (_ : a ∈ k • B), k • B
hfB_ne : B.Nonempty
k : G
⊢ a ∈ k • B → B' ⊆ k • B
Module: Mathlib.GroupTheory.GroupAction.Primitive

Goal state before:
pp: G : Type u_1
X : Type u_2
inst✝¹ : Group G
inst✝ : MulAction G X
a : X
ha : a ∉ fixedPoints G X
H : ∀ ⦃B : Set X⦄, a ∈ B → IsBlock G B → IsTrivialBlock B
⊢ ∀ (x : X), ∃ g, g • a = x

Tactic:
rcases H (mem_orbit_self a) (IsBlock.orbit a) with H | H

Goal state after:
case inl
G : Type u_1
X : Type u_2
inst✝¹ : Group G
inst✝ : MulAction G X
a : X
ha : a ∉ fixedPoints G X
H✝ : ∀ ⦃B : Set X⦄, a ∈ B → IsBlock G B → IsTrivialBlock B
H : (orbit G a).Subsingleton
⊢ ∀ (x : X), ∃ g, g • a = x

case inr
G : Type u_1
X : Type u_2
inst✝¹ : Group G
inst✝ : MulAction G X
a : X
ha : a ∉ fixedPoints G X
H✝ : ∀ ⦃B : Set X⦄, a ∈ B → IsBlock G B → IsTrivialBlock B
H : orbit G a = Set.univ
⊢ ∀ (x : X), ∃ g, g • a = x
Module: Mathlib.GroupTheory.GroupAction.SubMulAction.OfStabilizer

Goal state before:
pp: G : Type u_1
inst✝¹ : Group G
α : Type u_2
inst✝ : MulAction G α
a : α
t : Set ↥(ofStabilizer G a)
⊢ a ∉ Subtype.val '' t

Tactic:
rintro ⟨b, hb⟩

Goal state after:
G : Type u_1
inst✝¹ : Group G
α : Type u_2
inst✝ : MulAction G α
a : α
t : Set ↥(ofStabilizer G a)
b : ↥(ofStabilizer G a)
hb : b ∈ t ∧ ↑b = a
⊢ False
Module: Mathlib.GroupTheory.SpecificGroups.Alternating

Goal state before:
pp: case inr.refine_1
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
σ : Perm α
hσ✝ : σ ∈ alternatingGroup α
hσ : (↑⟨σ, hσ✝⟩).support.card + 2 ≤ card α
τ : Perm α
hτ : τ ∈ alternatingGroup α
hc : IsConj ↑⟨σ, hσ✝⟩ ↑⟨τ, hτ⟩
π : Perm α
hπ : π * σ * π⁻¹ = τ
h : sign π = -1
h2 : 2 ≤ σ.supportᶜ.card
a : α
ha : a ∈ σ.supportᶜ
b : α
hb : b ∈ σ.supportᶜ
ab : a ≠ b
⊢ sign π * sign (swap a b) = 1

Tactic:
h,

Goal state after:
case inr.refine_1
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
σ : Perm α
hσ✝ : σ ∈ alternatingGroup α
hσ : (↑⟨σ, hσ✝⟩).support.card + 2 ≤ card α
τ : Perm α
hτ : τ ∈ alternatingGroup α
hc : IsConj ↑⟨σ, hσ✝⟩ ↑⟨τ, hτ⟩
π : Perm α
hπ : π * σ * π⁻¹ = τ
h : sign π = -1
h2 : 2 ≤ σ.supportᶜ.card
a : α
ha : a ∈ σ.supportᶜ
b : α
hb : b ∈ σ.supportᶜ
ab : a ≠ b
⊢ -1 * sign (swap a b) = 1
Module: Mathlib.GroupTheory.GroupAction.Primitive

Goal state before:
pp: G : Type u_1
X : Type u_2
inst✝⁶ : Group G
inst✝⁵ : MulAction G X
H : Type u_3
Y : Type u_4
inst✝⁴ : Group H
inst✝³ : MulAction H Y
φ : G → H
f : X →ₑ[φ] Y
inst✝² : Finite Y
inst✝¹ : IsPretransitive H Y
inst✝ : IsPreprimitive G X
hf' : Nat.card Y < 2 * (Set.range ⇑f).ncard
B : Set Y
hB : IsBlock H B
hB' : B.Nonempty
hB_ne_top : ¬B = Set.univ
hfin : Fintype ↑(Set.range fun g ↦ g • B)
g : H
h : Set.range ⇑f ⊆ g • B
⊢ 2 * (Set.range ⇑f).ncard ≤ B.ncard * 2

Tactic:
rw [mul_comm, mul_le_mul_iff_left₀ Nat.succ_pos']

Goal state after:
G : Type u_1
X : Type u_2
inst✝⁶ : Group G
inst✝⁵ : MulAction G X
H : Type u_3
Y : Type u_4
inst✝⁴ : Group H
inst✝³ : MulAction H Y
φ : G → H
f : X →ₑ[φ] Y
inst✝² : Finite Y
inst✝¹ : IsPretransitive H Y
inst✝ : IsPreprimitive G X
hf' : Nat.card Y < 2 * (Set.range ⇑f).ncard
B : Set Y
hB : IsBlock H B
hB' : B.Nonempty
hB_ne_top : ¬B = Set.univ
hfin : Fintype ↑(Set.range fun g ↦ g • B)
g : H
h : Set.range ⇑f ⊆ g • B
⊢ (Set.range ⇑f).ncard ≤ B.ncard
Module: Mathlib.GroupTheory.SpecificGroups.Alternating

Goal state before:
pp: α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
⊢ IsMulCommutative ↥(alternatingGroup α) ↔ Nat.card α ≤ 3

Tactic:
by
  refine ⟨fun H ↦ ?_, fun h ↦ (isCyclic_of_card_le_three h).isMulCommutative⟩
  rw [← not_lt]
  intro h
  suffices Subsingleton (alternatingGroup α) by
    rw [← not_nontrivial_iff_subsingleton] at this
    apply this
    exact nontrivial_of_three_le_card h.le
  simpa [center_eq_top_iff.mpr H, eq_comm, subsingleton_iff_bot_eq_top] using center_eq_bot h

Goal state after: