-- Mathlib/GroupTheory/Perm/Cycle/Concrete.lean
theorem nodup_toList (p : Perm α) (x : α) : Nodup (toList p x)

Proof state:
case neg.succ.succ
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hx : x ∈ (p.cycleOf x).support
hc : (p.cycleOf x).IsCycle
n : ℕ
hn✝ : n + 1 < (p.toList x).length
hn : n + 1 < orderOf (p.cycleOf x)
m : ℕ
hm✝ : m + 1 < (p.toList x).length
hm : m + 1 < orderOf (p.cycleOf x)
h : (p.cycleOf x ^ (n + 1)) x = (p.cycleOf x ^ (m + 1)) x
hn' : (p.cycleOf x ^ n.succ).support = (p.cycleOf x).support
hm' : (p.cycleOf x ^ m.succ).support = (p.cycleOf x).support
⊢ p.cycleOf x ^ (n + 1) = p.cycleOf x ^ (m + 1)

Tactic:
refine support_congr ?_ ?_

Result:
case neg.succ.succ.refine_1
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hx : x ∈ (p.cycleOf x).support
hc : (p.cycleOf x).IsCycle
n : ℕ
hn✝ : n + 1 < (p.toList x).length
hn : n + 1 < orderOf (p.cycleOf x)
m : ℕ
hm✝ : m + 1 < (p.toList x).length
hm : m + 1 < orderOf (p.cycleOf x)
h : (p.cycleOf x ^ (n + 1)) x = (p.cycleOf x ^ (m + 1)) x
hn' : (p.cycleOf x ^ n.succ).support = (p.cycleOf x).support
hm' : (p.cycleOf x ^ m.succ).support = (p.cycleOf x).support
⊢ (p.cycleOf x ^ (n + 1)).support ⊆ (p.cycleOf x ^ (m + 1)).support

case neg.succ.succ.refine_2
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hx : x ∈ (p.cycleOf x).support
hc : (p.cycleOf x).IsCycle
n : ℕ
hn✝ : n + 1 < (p.toList x).length
hn : n + 1 < orderOf (p.cycleOf x)
m : ℕ
hm✝ : m + 1 < (p.toList x).length
hm : m + 1 < orderOf (p.cycleOf x)
h : (p.cycleOf x ^ (n + 1)) x = (p.cycleOf x ^ (m + 1)) x
hn' : (p.cycleOf x ^ n.succ).support = (p.cycleOf x).support
hm' : (p.cycleOf x ^ m.succ).support = (p.cycleOf x).support
⊢ ∀ x_1 ∈ (p.cycleOf x ^ (m + 1)).support, (p.cycleOf x ^ (n + 1)) x_1 = (p.cycleOf x ^ (m + 1)) x_1

Proof state:
case neg
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hx : ¬p x = x
⊢ (p.toList x).Nodup

Tactic:
have hc : IsCycle (cycleOf p x) := isCycle_cycleOf p hx

Result:
case neg
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hx : ¬p x = x
hc : (p.cycleOf x).IsCycle
⊢ (p.toList x).Nodup

Proof state:
case neg.succ.succ.refine_2
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hx : x ∈ (p.cycleOf x).support
hc : (p.cycleOf x).IsCycle
n : ℕ
hn✝ : n + 1 < (p.toList x).length
hn : n + 1 < orderOf (p.cycleOf x)
m : ℕ
hm✝ : m + 1 < (p.toList x).length
hm : m + 1 < orderOf (p.cycleOf x)
h : (p.cycleOf x ^ (n + 1)) x = (p.cycleOf x ^ (m + 1)) x
hn' : (p.cycleOf x ^ n.succ).support = (p.cycleOf x).support
hm' : (p.cycleOf x ^ m.succ).support = (p.cycleOf x).support
y : α
hy : y ∈ (p.cycleOf x).support
⊢ (p.cycleOf x ^ (n + 1)) y = (p.cycleOf x ^ (m + 1)) y

Tactic:
obtain ⟨k, rfl⟩ := hc.exists_pow_eq (mem_support.mp hx) (mem_support.mp hy)

Result:
case neg.succ.succ.refine_2.intro
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hx : x ∈ (p.cycleOf x).support
hc : (p.cycleOf x).IsCycle
n : ℕ
hn✝ : n + 1 < (p.toList x).length
hn : n + 1 < orderOf (p.cycleOf x)
m : ℕ
hm✝ : m + 1 < (p.toList x).length
hm : m + 1 < orderOf (p.cycleOf x)
h : (p.cycleOf x ^ (n + 1)) x = (p.cycleOf x ^ (m + 1)) x
hn' : (p.cycleOf x ^ n.succ).support = (p.cycleOf x).support
hm' : (p.cycleOf x ^ m.succ).support = (p.cycleOf x).support
k : ℕ
hy : (p.cycleOf x ^ k) x ∈ (p.cycleOf x).support
⊢ (p.cycleOf x ^ (n + 1)) ((p.cycleOf x ^ k) x) = (p.cycleOf x ^ (m + 1)) ((p.cycleOf x ^ k) x)

Proof state:
case neg.zero.succ
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hx : x ∈ (p.cycleOf x).support
hc : (p.cycleOf x).IsCycle
hn✝ : 0 < (p.toList x).length
hn : 0 < orderOf (p.cycleOf x)
m : ℕ
hm✝ : m + 1 < (p.toList x).length
hm : m + 1 < orderOf (p.cycleOf x)
⊢ (p.cycleOf x ^ 0) x = (p.cycleOf x ^ (m + 1)) x → 0 = m + 1

Tactic:
rw [← hc.support_pow_of_pos_of_lt_orderOf m.zero_lt_succ hm, mem_support,
  cycleOf_pow_apply_self] at hx

Result:
case neg.zero.succ
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hc : (p.cycleOf x).IsCycle
hn✝ : 0 < (p.toList x).length
hn : 0 < orderOf (p.cycleOf x)
m : ℕ
hx : (p ^ m.succ) x ≠ x
hm✝ : m + 1 < (p.toList x).length
hm : m + 1 < orderOf (p.cycleOf x)
⊢ (p.cycleOf x ^ 0) x = (p.cycleOf x ^ (m + 1)) x → 0 = m + 1

Proof state:
case pos
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hx : p.toList x = []
⊢ (p.toList x).Nodup

Tactic:
simp [hx]

Result:
no goals

Proof state:
case neg.succ.succ
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hx : x ∈ (p.cycleOf x).support
hc : (p.cycleOf x).IsCycle
n : ℕ
hn✝ : n + 1 < (p.toList x).length
hn : n + 1 < orderOf (p.cycleOf x)
m : ℕ
hm✝ : m + 1 < (p.toList x).length
hm : m + 1 < orderOf (p.cycleOf x)
h : (p.cycleOf x ^ (n + 1)) x = (p.cycleOf x ^ (m + 1)) x
⊢ n + 1 = m + 1

Tactic:
have hn' : ¬orderOf (p.cycleOf x) ∣ n.succ := Nat.not_dvd_of_pos_of_lt n.zero_lt_succ hn

Result:
case neg.succ.succ
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hx : x ∈ (p.cycleOf x).support
hc : (p.cycleOf x).IsCycle
n : ℕ
hn✝ : n + 1 < (p.toList x).length
hn : n + 1 < orderOf (p.cycleOf x)
m : ℕ
hm✝ : m + 1 < (p.toList x).length
hm : m + 1 < orderOf (p.cycleOf x)
h : (p.cycleOf x ^ (n + 1)) x = (p.cycleOf x ^ (m + 1)) x
hn' : ¬orderOf (p.cycleOf x) ∣ n.succ
⊢ n + 1 = m + 1

Proof state:
case neg.succ.succ.refine_2
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hx : x ∈ (p.cycleOf x).support
hc : (p.cycleOf x).IsCycle
n : ℕ
hn✝ : n + 1 < (p.toList x).length
hn : n + 1 < orderOf (p.cycleOf x)
m : ℕ
hm✝ : m + 1 < (p.toList x).length
hm : m + 1 < orderOf (p.cycleOf x)
h : (p.cycleOf x ^ (n + 1)) x = (p.cycleOf x ^ (m + 1)) x
hn' : (p.cycleOf x ^ n.succ).support = (p.cycleOf x).support
hm' : (p.cycleOf x ^ m.succ).support = (p.cycleOf x).support
⊢ ∀ x_1 ∈ (p.cycleOf x).support, (p.cycleOf x ^ (n + 1)) x_1 = (p.cycleOf x ^ (m + 1)) x_1

Tactic:
intro y hy

Result:
case neg.succ.succ.refine_2
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hx : x ∈ (p.cycleOf x).support
hc : (p.cycleOf x).IsCycle
n : ℕ
hn✝ : n + 1 < (p.toList x).length
hn : n + 1 < orderOf (p.cycleOf x)
m : ℕ
hm✝ : m + 1 < (p.toList x).length
hm : m + 1 < orderOf (p.cycleOf x)
h : (p.cycleOf x ^ (n + 1)) x = (p.cycleOf x ^ (m + 1)) x
hn' : (p.cycleOf x ^ n.succ).support = (p.cycleOf x).support
hm' : (p.cycleOf x ^ m.succ).support = (p.cycleOf x).support
y : α
hy : y ∈ (p.cycleOf x).support
⊢ (p.cycleOf x ^ (n + 1)) y = (p.cycleOf x ^ (m + 1)) y

Proof state:
case neg.succ.succ.refine_2
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hx : x ∈ (p.cycleOf x).support
hc : (p.cycleOf x).IsCycle
n : ℕ
hn✝ : n + 1 < (p.toList x).length
hn : n + 1 < orderOf (p.cycleOf x)
m : ℕ
hm✝ : m + 1 < (p.toList x).length
hm : m + 1 < orderOf (p.cycleOf x)
h : (p.cycleOf x ^ (n + 1)) x = (p.cycleOf x ^ (m + 1)) x
hn' : (p.cycleOf x ^ n.succ).support = (p.cycleOf x).support
hm' : (p.cycleOf x ^ m.succ).support = (p.cycleOf x).support
⊢ ∀ x_1 ∈ (p.cycleOf x ^ (m + 1)).support, (p.cycleOf x ^ (n + 1)) x_1 = (p.cycleOf x ^ (m + 1)) x_1

Tactic:
rw [hm']

Result:
case neg.succ.succ.refine_2
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
p : Perm α
x : α
hx : x ∈ (p.cycleOf x).support
hc : (p.cycleOf x).IsCycle
n : ℕ
hn✝ : n + 1 < (p.toList x).length
hn : n + 1 < orderOf (p.cycleOf x)
m : ℕ
hm✝ : m + 1 < (p.toList x).length
hm : m + 1 < orderOf (p.cycleOf x)
h : (p.cycleOf x ^ (n + 1)) x = (p.cycleOf x ^ (m + 1)) x
hn' : (p.cycleOf x ^ n.succ).support = (p.cycleOf x).support
hm' : (p.cycleOf x ^ m.succ).support = (p.cycleOf x).support
⊢ ∀ x_1 ∈ (p.cycleOf x).support, (p.cycleOf x ^ (n + 1)) x_1 = (p.cycleOf x ^ (m + 1)) x_1