Module: Mathlib.RingTheory.ChainOfDivisors

Goal state before:
pp: case neg
M : Type u_1
inst✝⁴ : CommMonoidWithZero M
inst✝³ : IsCancelMulZero M
N : Type u_2
inst✝² : CommMonoidWithZero N
inst✝¹ : UniqueFactorizationMonoid N
inst✝ : UniqueFactorizationMonoid M
m : Associates M
n : Associates N
hn : n ≠ 0
d : ↑(Set.Iic m) ≃o ↑(Set.Iic n)
s : ℕ
hs : ¬s = 0
c₁ : Fin (s + 1) → Associates M
hp : c₁ 1 ∈ normalizedFactors m
hs' : c₁ 1 ^ s ≤ m
hc₁' : StrictMono c₁
hc₁'' : ∀ {r : Associates M}, r ≤ c₁ 1 ^ s ↔ ∃ i, r = c₁ i
c₂ : Fin (s + 1) → Associates N := fun t ↦ ↑(d ⟨c₁ t, ⋯⟩)
c₂_def : ∀ (t : Fin (s + 1)), c₂ t = ↑(d ⟨c₁ t, ⋯⟩)
⊢ c₂ 1 ^ s = ↑(d ⟨c₁ 1 ^ s, hs'⟩)

Tactic:
refine (eq_pow_second_of_chain_of_has_chain hs (fun t u h => ?_)
    (@fun r => ⟨@fun hr => ?_, ?_⟩) ?_).symm

Goal state after:
case neg.refine_1
M : Type u_1
inst✝⁴ : CommMonoidWithZero M
inst✝³ : IsCancelMulZero M
N : Type u_2
inst✝² : CommMonoidWithZero N
inst✝¹ : UniqueFactorizationMonoid N
inst✝ : UniqueFactorizationMonoid M
m : Associates M
n : Associates N
hn : n ≠ 0
d : ↑(Set.Iic m) ≃o ↑(Set.Iic n)
s : ℕ
hs : ¬s = 0
c₁ : Fin (s + 1) → Associates M
hp : c₁ 1 ∈ normalizedFactors m
hs' : c₁ 1 ^ s ≤ m
hc₁' : StrictMono c₁
hc₁'' : ∀ {r : Associates M}, r ≤ c₁ 1 ^ s ↔ ∃ i, r = c₁ i
c₂ : Fin (s + 1) → Associates N := fun t ↦ ↑(d ⟨c₁ t, ⋯⟩)
c₂_def : ∀ (t : Fin (s + 1)), c₂ t = ↑(d ⟨c₁ t, ⋯⟩)
t u : Fin (s + 1)
h : t < u
⊢ c₂ t < c₂ u

case neg.refine_2
M : Type u_1
inst✝⁴ : CommMonoidWithZero M
inst✝³ : IsCancelMulZero M
N : Type u_2
inst✝² : CommMonoidWithZero N
inst✝¹ : UniqueFactorizationMonoid N
inst✝ : UniqueFactorizationMonoid M
m : Associates M
n : Associates N
hn : n ≠ 0
d : ↑(Set.Iic m) ≃o ↑(Set.Iic n)
s : ℕ
hs : ¬s = 0
c₁ : Fin (s + 1) → Associates M
hp : c₁ 1 ∈ normalizedFactors m
hs' : c₁ 1 ^ s ≤ m
hc₁' : StrictMono c₁
hc₁'' : ∀ {r : Associates M}, r ≤ c₁ 1 ^ s ↔ ∃ i, r = c₁ i
c₂ : Fin (s + 1) → Associates N := fun t ↦ ↑(d ⟨c₁ t, ⋯⟩)
c₂_def : ∀ (t : Fin (s + 1)), c₂ t = ↑(d ⟨c₁ t, ⋯⟩)
r : Associates N
hr : r ≤ ↑(d ⟨c₁ 1 ^ s, hs'⟩)
⊢ ∃ i, r = c₂ i

case neg.refine_3
M : Type u_1
inst✝⁴ : CommMonoidWithZero M
inst✝³ : IsCancelMulZero M
N : Type u_2
inst✝² : CommMonoidWithZero N
inst✝¹ : UniqueFactorizationMonoid N
inst✝ : UniqueFactorizationMonoid M
m : Associates M
n : Associates N
hn : n ≠ 0
d : ↑(Set.Iic m) ≃o ↑(Set.Iic n)
s : ℕ
hs : ¬s = 0
c₁ : Fin (s + 1) → Associates M
hp : c₁ 1 ∈ normalizedFactors m
hs' : c₁ 1 ^ s ≤ m
hc₁' : StrictMono c₁
hc₁'' : ∀ {r : Associates M}, r ≤ c₁ 1 ^ s ↔ ∃ i, r = c₁ i
c₂ : Fin (s + 1) → Associates N := fun t ↦ ↑(d ⟨c₁ t, ⋯⟩)
c₂_def : ∀ (t : Fin (s + 1)), c₂ t = ↑(d ⟨c₁ t, ⋯⟩)
r : Associates N
⊢ (∃ i, r = c₂ i) → r ≤ ↑(d ⟨c₁ 1 ^ s, hs'⟩)

case neg.refine_4
M : Type u_1
inst✝⁴ : CommMonoidWithZero M
inst✝³ : IsCancelMulZero M
N : Type u_2
inst✝² : CommMonoidWithZero N
inst✝¹ : UniqueFactorizationMonoid N
inst✝ : UniqueFactorizationMonoid M
m : Associates M
n : Associates N
hn : n ≠ 0
d : ↑(Set.Iic m) ≃o ↑(Set.Iic n)
s : ℕ
hs : ¬s = 0
c₁ : Fin (s + 1) → Associates M
hp : c₁ 1 ∈ normalizedFactors m
hs' : c₁ 1 ^ s ≤ m
hc₁' : StrictMono c₁
hc₁'' : ∀ {r : Associates M}, r ≤ c₁ 1 ^ s ↔ ∃ i, r = c₁ i
c₂ : Fin (s + 1) → Associates N := fun t ↦ ↑(d ⟨c₁ t, ⋯⟩)
c₂_def : ∀ (t : Fin (s + 1)), c₂ t = ↑(d ⟨c₁ t, ⋯⟩)
⊢ ↑(d ⟨c₁ 1 ^ s, hs'⟩) ≠ 0