-- Mathlib/RingTheory/DiscreteValuationRing/Basic.lean
theorem unique_irreducible (hR : HasUnitMulPowIrreducibleFactorization R)
    ⦃p q : R⦄ (hp : Irreducible p) (hq : Irreducible q) :
    Associated p q

Proof state:
case intro.intro.intro.inr.inr.intro.inl
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ (1 + n + 1)) p
this : Irreducible (ϖ * ϖ ^ (1 + n))
H : 1 < 1 + n + 1
H0 : IsUnit ϖ
⊢ Associated p ϖ

Tactic:
exact (hϖ.not_unit H0).elim

Result:
no goals

Proof state:
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
H : n < 1
⊢ n = 0

Tactic:
revert H n

Result:
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
⊢ ∀ n < 1, n = 0

Proof state:
case intro.intro.intro.inr.inr.intro.inr
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ (1 + n + 1)) p
this : Irreducible (ϖ * ϖ ^ (1 + n))
H : 1 < 1 + n + 1
H0 : IsUnit (ϖ * ϖ ^ n)
⊢ Associated p ϖ

Tactic:
exact (hϖ.not_unit (isUnit_of_mul_isUnit_left H0)).elim

Result:
no goals

Proof state:
case intro.intro.intro.inl
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
hn : Associated (ϖ ^ 0) p
this : Irreducible (ϖ ^ 0)
H : 0 < 1
⊢ Associated p ϖ

Tactic:
simp [not_irreducible_one, pow_zero] at this

Result:
no goals

Proof state:
case intro.intro.intro.inr.inr.intro
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ (1 + n + 1)) p
this : Irreducible (ϖ ^ (1 + n + 1))
H : 1 < 1 + n + 1
⊢ Associated p ϖ

Tactic:
rw [pow_succ'] at this

Result:
case intro.intro.intro.inr.inr.intro
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ (1 + n + 1)) p
this : Irreducible (ϖ * ϖ ^ (1 + n))
H : 1 < 1 + n + 1
⊢ Associated p ϖ

Proof state:
case intro.intro.intro
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ n) p
this : Irreducible (ϖ ^ n)
⊢ Associated p ϖ

Tactic:
rcases lt_trichotomy n 1 with (H | rfl | H)

Result:
case intro.intro.intro.inl
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ n) p
this : Irreducible (ϖ ^ n)
H : n < 1
⊢ Associated p ϖ

case intro.intro.intro.inr.inl
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
hn : Associated (ϖ ^ 1) p
this : Irreducible (ϖ ^ 1)
⊢ Associated p ϖ

case intro.intro.intro.inr.inr
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ n) p
this : Irreducible (ϖ ^ n)
H : 1 < n
⊢ Associated p ϖ

Proof state:
case intro.intro.intro.inr.inr.intro
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ (1 + n + 1)) p
this : Irreducible (ϖ * ϖ ^ (1 + n))
H : 1 < 1 + n + 1
⊢ Associated p ϖ

Tactic:
rcases this.isUnit_or_isUnit rfl with (H0 | H0)

Result:
case intro.intro.intro.inr.inr.intro.inl
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ (1 + n + 1)) p
this : Irreducible (ϖ * ϖ ^ (1 + n))
H : 1 < 1 + n + 1
H0 : IsUnit ϖ
⊢ Associated p ϖ

case intro.intro.intro.inr.inr.intro.inr
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ (1 + n + 1)) p
this : Irreducible (ϖ * ϖ ^ (1 + n))
H : 1 < 1 + n + 1
H0 : IsUnit (ϖ ^ (1 + n))
⊢ Associated p ϖ

Proof state:
case intro.intro.intro
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ n) p
⊢ Associated p ϖ

Tactic:
have : Irreducible (ϖ ^ n) := hn.symm.irreducible hp

Result:
case intro.intro.intro
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ n) p
this : Irreducible (ϖ ^ n)
⊢ Associated p ϖ

Proof state:
case intro.intro
R : Type u_1
inst✝ : CommRing R
p q : R
hp : Irreducible p
hq : Irreducible q
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
⊢ Associated p q

Tactic:
suffices ∀ {p : R} (_ : Irreducible p), Associated p ϖ by
  apply Associated.trans (this hp) (this hq).symm

Result:
case intro.intro
R : Type u_1
inst✝ : CommRing R
p q : R
hp : Irreducible p
hq : Irreducible q
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
⊢ ∀ {p : R}, Irreducible p → Associated p ϖ

Proof state:
case intro.intro
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
⊢ ∀ {p : R}, Irreducible p → Associated p ϖ

Tactic:
intro p hp

Result:
case intro.intro
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
⊢ Associated p ϖ

Proof state:
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ n) p
this : Irreducible (ϖ ^ n)
H : n < 1
⊢ n = 0

Tactic:
clear hn this

Result:
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
H : n < 1
⊢ n = 0

Proof state:
case intro.intro.intro.inr.inl
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
hn : Associated (ϖ ^ 1) p
this : Irreducible (ϖ ^ 1)
⊢ Associated p ϖ

Tactic:
simpa only [pow_one] using hn.symm

Result:
no goals

Proof state:
case intro.intro.intro.inr.inr
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ n) p
this : Irreducible (ϖ ^ n)
H : 1 < n
⊢ Associated p ϖ

Tactic:
obtain ⟨n, rfl⟩ : ∃ k, n = 1 + k + 1 := Nat.exists_eq_add_of_lt H

Result:
case intro.intro.intro.inr.inr.intro
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ (1 + n + 1)) p
this : Irreducible (ϖ ^ (1 + n + 1))
H : 1 < 1 + n + 1
⊢ Associated p ϖ

Proof state:
case intro.intro
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
⊢ Associated p ϖ

Tactic:
obtain ⟨n, hn⟩ := hR hp.ne_zero

Result:
case intro.intro.intro
R : Type u_1
inst✝ : CommRing R
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
p : R
hp : Irreducible p
n : ℕ
hn : Associated (ϖ ^ n) p
⊢ Associated p ϖ

Proof state:
R : Type u_1
inst✝ : CommRing R
p q : R
hp : Irreducible p
hq : Irreducible q
ϖ : R
hϖ : Irreducible ϖ
hR : ∀ {x : R}, x ≠ 0 → ∃ n, Associated (ϖ ^ n) x
this : ∀ {p : R}, Irreducible p → Associated p ϖ
⊢ Associated p q

Tactic:
apply Associated.trans (this hp) (this hq).symm

Result:
no goals