Theorem: Equiv.Perm.cycleFactorsFinset_mul_inv_mem_eq_sdiff
File: Mathlib/GroupTheory/Perm/Cycle/Factors.lean

tactic: revert f
state_before: ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
f g : Perm α
h : f ∈ g.cycleFactorsFinset
⊢ (g * f⁻¹).cycleFactorsFinset = g.cycleFactorsFinset \ {f}
state_after: ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g : Perm α
⊢ ∀ {f : Perm α}, f ∈ g.cycleFactorsFinset → (g * f⁻¹).cycleFactorsFinset = g.cycleFactorsFinset \ {f}

tactic: refine
  cycle_induction_on (P := fun {g : Perm α} ↦
    ∀ {f}, (f ∈ cycleFactorsFinset g)
      → cycleFactorsFinset (g * f⁻¹) = cycleFactorsFinset g \ {f}) _ ?_ ?_ ?_
state_before: ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g : Perm α
⊢ ∀ {f : Perm α}, f ∈ g.cycleFactorsFinset → (g * f⁻¹).cycleFactorsFinset = g.cycleFactorsFinset \ {f}
state_after: case refine_1
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ : Perm α
⊢ fun {g} => ∀ {f : Perm α}, f ∈ g.cycleFactorsFinset → (g * f⁻¹).cycleFactorsFinset = g.cycleFactorsFinset \ {f}

case refine_2
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ : Perm α
⊢ ∀ (σ : Perm α),
    σ.IsCycle → fun {g} =>
      ∀ {f : Perm α}, f ∈ g.cycleFactorsFinset → (g * f⁻¹).cycleFactorsFinset = g.cycleFactorsFinset \ {f}

case refine_3
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ : Perm α
⊢ ∀ (σ τ : Perm α),
    σ.Disjoint τ →
      σ.IsCycle →
        (fun {g} =>
            ∀ {f : Perm α}, f ∈ g.cycleFactorsFinset → (g * f⁻¹).cycleFactorsFinset = g.cycleFactorsFinset \ {f}) →
          (fun {g} =>
              ∀ {f : Perm α}, f ∈ g.cycleFactorsFinset → (g * f⁻¹).cycleFactorsFinset = g.cycleFactorsFinset \ {f}) →
            fun {g} =>
            ∀ {f : Perm α}, f ∈ g.cycleFactorsFinset → (g * f⁻¹).cycleFactorsFinset = g.cycleFactorsFinset \ {f}

tactic: simp
state_before: case refine_1
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ : Perm α
⊢ fun {g} => ∀ {f : Perm α}, f ∈ g.cycleFactorsFinset → (g * f⁻¹).cycleFactorsFinset = g.cycleFactorsFinset \ {f}
state_after: no goals

tactic: intro σ hσ f hf
state_before: case refine_2
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ : Perm α
⊢ ∀ (σ : Perm α),
    σ.IsCycle → fun {g} =>
      ∀ {f : Perm α}, f ∈ g.cycleFactorsFinset → (g * f⁻¹).cycleFactorsFinset = g.cycleFactorsFinset \ {f}
state_after: case refine_2
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ : Perm α
hσ : σ.IsCycle
f : Perm α
hf : f ∈ σ.cycleFactorsFinset
⊢ (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}

tactic: simp only [cycleFactorsFinset_eq_singleton_self_iff.mpr hσ, mem_singleton] at hf ⊢
state_before: case refine_2
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ : Perm α
hσ : σ.IsCycle
f : Perm α
hf : f ∈ σ.cycleFactorsFinset
⊢ (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
state_after: case refine_2
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ : Perm α
hσ : σ.IsCycle
f : Perm α
hf : f = σ
⊢ (σ * f⁻¹).cycleFactorsFinset = {σ} \ {f}

tactic: simp [hf]
state_before: case refine_2
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ : Perm α
hσ : σ.IsCycle
f : Perm α
hf : f = σ
⊢ (σ * f⁻¹).cycleFactorsFinset = {σ} \ {f}
state_after: no goals

tactic: intro σ τ hd _ hσ hτ f
state_before: case refine_3
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ : Perm α
⊢ ∀ (σ τ : Perm α),
    σ.Disjoint τ →
      σ.IsCycle →
        (fun {g} =>
            ∀ {f : Perm α}, f ∈ g.cycleFactorsFinset → (g * f⁻¹).cycleFactorsFinset = g.cycleFactorsFinset \ {f}) →
          (fun {g} =>
              ∀ {f : Perm α}, f ∈ g.cycleFactorsFinset → (g * f⁻¹).cycleFactorsFinset = g.cycleFactorsFinset \ {f}) →
            fun {g} =>
            ∀ {f : Perm α}, f ∈ g.cycleFactorsFinset → (g * f⁻¹).cycleFactorsFinset = g.cycleFactorsFinset \ {f}
state_after: case refine_3
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
⊢ f ∈ (σ * τ).cycleFactorsFinset → (σ * τ * f⁻¹).cycleFactorsFinset = (σ * τ).cycleFactorsFinset \ {f}

tactic: simp_rw [hd.cycleFactorsFinset_mul_eq_union, mem_union]
state_before: case refine_3
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
⊢ f ∈ (σ * τ).cycleFactorsFinset → (σ * τ * f⁻¹).cycleFactorsFinset = (σ * τ).cycleFactorsFinset \ {f}
state_after: case refine_3
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
⊢ f ∈ σ.cycleFactorsFinset ∨ f ∈ τ.cycleFactorsFinset →
    (σ * τ * f⁻¹).cycleFactorsFinset = (σ.cycleFactorsFinset ∪ τ.cycleFactorsFinset) \ {f}

tactic: rintro (hf | hf)
state_before: case refine_3
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
⊢ f ∈ σ.cycleFactorsFinset ∨ f ∈ τ.cycleFactorsFinset →
    (σ * τ * f⁻¹).cycleFactorsFinset = (σ.cycleFactorsFinset ∪ τ.cycleFactorsFinset) \ {f}
state_after: case refine_3.inl
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f ∈ σ.cycleFactorsFinset
⊢ (σ * τ * f⁻¹).cycleFactorsFinset = (σ.cycleFactorsFinset ∪ τ.cycleFactorsFinset) \ {f}

case refine_3.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f ∈ τ.cycleFactorsFinset
⊢ (σ * τ * f⁻¹).cycleFactorsFinset = (σ.cycleFactorsFinset ∪ τ.cycleFactorsFinset) \ {f}

tactic: rw [hd.commute.eq, union_comm, union_sdiff_distrib, sdiff_singleton_eq_erase,
  erase_eq_of_not_mem, mul_assoc, Disjoint.cycleFactorsFinset_mul_eq_union, hσ hf]
state_before: case refine_3.inl
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f ∈ σ.cycleFactorsFinset
⊢ (σ * τ * f⁻¹).cycleFactorsFinset = (σ.cycleFactorsFinset ∪ τ.cycleFactorsFinset) \ {f}
state_after: case refine_3.inl
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f ∈ σ.cycleFactorsFinset
⊢ τ.Disjoint (σ * f⁻¹)

case refine_3.inl
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f ∈ σ.cycleFactorsFinset
⊢ f ∉ τ.cycleFactorsFinset

tactic: rw [mem_cycleFactorsFinset_iff] at hf
state_before: case refine_3.inl
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f ∈ σ.cycleFactorsFinset
⊢ τ.Disjoint (σ * f⁻¹)
state_after: case refine_3.inl
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
⊢ τ.Disjoint (σ * f⁻¹)

tactic: intro x
state_before: case refine_3.inl
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
⊢ τ.Disjoint (σ * f⁻¹)
state_after: case refine_3.inl
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
⊢ τ x = x ∨ (σ * f⁻¹) x = x

tactic: cases' hd.symm x with hx hx
state_before: case refine_3.inl
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
⊢ τ x = x ∨ (σ * f⁻¹) x = x
state_after: case refine_3.inl.inl
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : τ x = x
⊢ τ x = x ∨ (σ * f⁻¹) x = x

case refine_3.inl.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : σ x = x
⊢ τ x = x ∨ (σ * f⁻¹) x = x

tactic: exact Or.inl hx
state_before: case refine_3.inl.inl
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : τ x = x
⊢ τ x = x ∨ (σ * f⁻¹) x = x
state_after: no goals

tactic: refine Or.inr ?_
state_before: case refine_3.inl.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : σ x = x
⊢ τ x = x ∨ (σ * f⁻¹) x = x
state_after: case refine_3.inl.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : σ x = x
⊢ (σ * f⁻¹) x = x

tactic: by_cases hfx : f x = x
state_before: case refine_3.inl.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : σ x = x
⊢ (σ * f⁻¹) x = x
state_after: case pos
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : σ x = x
hfx : f x = x
⊢ (σ * f⁻¹) x = x

case neg
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : σ x = x
hfx : ¬f x = x
⊢ (σ * f⁻¹) x = x

tactic: rw [← hfx]
state_before: case pos
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : σ x = x
hfx : f x = x
⊢ (σ * f⁻¹) x = x
state_after: case pos
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : σ x = x
hfx : f x = x
⊢ (σ * f⁻¹) (f x) = f x

tactic: simpa [hx] using hfx.symm
state_before: case pos
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : σ x = x
hfx : f x = x
⊢ (σ * f⁻¹) (f x) = f x
state_after: no goals

tactic: rw [mul_apply]
state_before: case neg
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : σ x = x
hfx : ¬f x = x
⊢ (σ * f⁻¹) x = x
state_after: case neg
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : σ x = x
hfx : ¬f x = x
⊢ σ (f⁻¹ x) = x

tactic: rw [← hf.right _ (mem_support.mpr hfx)] at hx
state_before: case neg
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : σ x = x
hfx : ¬f x = x
⊢ σ (f⁻¹ x) = x
state_after: case neg
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : f x = x
hfx : ¬f x = x
⊢ σ (f⁻¹ x) = x

tactic: contradiction
state_before: case neg
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = σ a
x : α
hx : f x = x
hfx : ¬f x = x
⊢ σ (f⁻¹ x) = x
state_after: no goals

tactic: exact fun H =>
not_mem_empty _ (hd.disjoint_cycleFactorsFinset.le_bot (mem_inter_of_mem hf H))
state_before: case refine_3.inl
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f ∈ σ.cycleFactorsFinset
⊢ f ∉ τ.cycleFactorsFinset
state_after: no goals

tactic: rw [union_sdiff_distrib, sdiff_singleton_eq_erase, erase_eq_of_not_mem, mul_assoc,
  Disjoint.cycleFactorsFinset_mul_eq_union, hτ hf]
state_before: case refine_3.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f ∈ τ.cycleFactorsFinset
⊢ (σ * τ * f⁻¹).cycleFactorsFinset = (σ.cycleFactorsFinset ∪ τ.cycleFactorsFinset) \ {f}
state_after: case refine_3.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f ∈ τ.cycleFactorsFinset
⊢ σ.Disjoint (τ * f⁻¹)

case refine_3.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f ∈ τ.cycleFactorsFinset
⊢ f ∉ σ.cycleFactorsFinset

tactic: rw [mem_cycleFactorsFinset_iff] at hf
state_before: case refine_3.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f ∈ τ.cycleFactorsFinset
⊢ σ.Disjoint (τ * f⁻¹)
state_after: case refine_3.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
⊢ σ.Disjoint (τ * f⁻¹)

tactic: intro x
state_before: case refine_3.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
⊢ σ.Disjoint (τ * f⁻¹)
state_after: case refine_3.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
⊢ σ x = x ∨ (τ * f⁻¹) x = x

tactic: cases' hd x with hx hx
state_before: case refine_3.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
⊢ σ x = x ∨ (τ * f⁻¹) x = x
state_after: case refine_3.inr.inl
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : σ x = x
⊢ σ x = x ∨ (τ * f⁻¹) x = x

case refine_3.inr.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : τ x = x
⊢ σ x = x ∨ (τ * f⁻¹) x = x

tactic: exact Or.inl hx
state_before: case refine_3.inr.inl
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : σ x = x
⊢ σ x = x ∨ (τ * f⁻¹) x = x
state_after: no goals

tactic: refine Or.inr ?_
state_before: case refine_3.inr.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : τ x = x
⊢ σ x = x ∨ (τ * f⁻¹) x = x
state_after: case refine_3.inr.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : τ x = x
⊢ (τ * f⁻¹) x = x

tactic: by_cases hfx : f x = x
state_before: case refine_3.inr.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : τ x = x
⊢ (τ * f⁻¹) x = x
state_after: case pos
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : τ x = x
hfx : f x = x
⊢ (τ * f⁻¹) x = x

case neg
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : τ x = x
hfx : ¬f x = x
⊢ (τ * f⁻¹) x = x

tactic: rw [← hfx]
state_before: case pos
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : τ x = x
hfx : f x = x
⊢ (τ * f⁻¹) x = x
state_after: case pos
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : τ x = x
hfx : f x = x
⊢ (τ * f⁻¹) (f x) = f x

tactic: simpa [hx] using hfx.symm
state_before: case pos
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : τ x = x
hfx : f x = x
⊢ (τ * f⁻¹) (f x) = f x
state_after: no goals

tactic: rw [mul_apply]
state_before: case neg
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : τ x = x
hfx : ¬f x = x
⊢ (τ * f⁻¹) x = x
state_after: case neg
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : τ x = x
hfx : ¬f x = x
⊢ τ (f⁻¹ x) = x

tactic: rw [← hf.right _ (mem_support.mpr hfx)] at hx
state_before: case neg
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : τ x = x
hfx : ¬f x = x
⊢ τ (f⁻¹ x) = x
state_after: case neg
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : f x = x
hfx : ¬f x = x
⊢ τ (f⁻¹ x) = x

tactic: contradiction
state_before: case neg
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f.IsCycle ∧ ∀ a ∈ f.support, f a = τ a
x : α
hx : f x = x
hfx : ¬f x = x
⊢ τ (f⁻¹ x) = x
state_after: no goals

tactic: exact fun H =>
not_mem_empty _ (hd.disjoint_cycleFactorsFinset.le_bot (mem_inter_of_mem H hf))
state_before: case refine_3.inr
ι : Type u_1
α : Type u_2
β : Type u_3
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g f✝ σ τ : Perm α
hd : σ.Disjoint τ
a✝ : σ.IsCycle
hσ : ∀ {f : Perm α}, f ∈ σ.cycleFactorsFinset → (σ * f⁻¹).cycleFactorsFinset = σ.cycleFactorsFinset \ {f}
hτ : ∀ {f : Perm α}, f ∈ τ.cycleFactorsFinset → (τ * f⁻¹).cycleFactorsFinset = τ.cycleFactorsFinset \ {f}
f : Perm α
hf : f ∈ τ.cycleFactorsFinset
⊢ f ∉ σ.cycleFactorsFinset
state_after: no goals