Theorem: Polynomial.IsUnitTrinomial.irreducible_of_coprime'
File: Mathlib/Algebra/Polynomial/UnitTrinomial.lean

tactic: refine hp.irreducible_of_coprime fun q hq hq' => ?_
state_before: p q : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
⊢ Irreducible p
state_after: p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
⊢ IsUnit q

tactic: suffices ¬0 < q.natDegree by
  rcases hq with ⟨p, rfl⟩
  replace hp := hp.leadingCoeff_isUnit
  rw [leadingCoeff_mul] at hp
  replace hp := isUnit_of_mul_isUnit_left hp
  rw [not_lt, Nat.le_zero] at this
  rwa [eq_C_of_natDegree_eq_zero this, isUnit_C, ← this]
state_before: p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
⊢ IsUnit q
state_after: p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
⊢ ¬0 < q.natDegree

tactic: intro hq''
state_before: p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
⊢ ¬0 < q.natDegree
state_after: p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
hq'' : 0 < q.natDegree
⊢ False

tactic: rw [natDegree_pos_iff_degree_pos] at hq''
state_before: p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
hq'' : 0 < q.natDegree
⊢ False
state_after: p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
hq'' : 0 < q.degree
⊢ False

tactic: rw [← degree_map_eq_of_injective (algebraMap ℤ ℂ).injective_int] at hq''
state_before: p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
hq'' : 0 < q.degree
⊢ False
state_after: p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
hq'' : 0 < (map (algebraMap ℤ ℂ) q).degree
⊢ False

tactic: cases' Complex.exists_root hq'' with z hz
state_before: p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
hq'' : 0 < (map (algebraMap ℤ ℂ) q).degree
⊢ False
state_after: case intro
p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
hq'' : 0 < (map (algebraMap ℤ ℂ) q).degree
z : ℂ
hz : (map (algebraMap ℤ ℂ) q).IsRoot z
⊢ False

tactic: rw [IsRoot, eval_map, ← aeval_def] at hz
state_before: case intro
p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
hq'' : 0 < (map (algebraMap ℤ ℂ) q).degree
z : ℂ
hz : (map (algebraMap ℤ ℂ) q).IsRoot z
⊢ False
state_after: case intro
p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
hq'' : 0 < (map (algebraMap ℤ ℂ) q).degree
z : ℂ
hz : (aeval z) q = 0
⊢ False

tactic: refine h z ⟨?_, ?_⟩
state_before: case intro
p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
hq'' : 0 < (map (algebraMap ℤ ℂ) q).degree
z : ℂ
hz : (aeval z) q = 0
⊢ False
state_after: case intro.refine_1
p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
hq'' : 0 < (map (algebraMap ℤ ℂ) q).degree
z : ℂ
hz : (aeval z) q = 0
⊢ (aeval z) p = 0

case intro.refine_2
p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
hq'' : 0 < (map (algebraMap ℤ ℂ) q).degree
z : ℂ
hz : (aeval z) q = 0
⊢ (aeval z) p.mirror = 0

tactic: rcases hq with ⟨p, rfl⟩
state_before: p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
this : ¬0 < q.natDegree
⊢ IsUnit q
state_after: case intro
q✝ q : ℤ[X]
this : ¬0 < q.natDegree
p : ℤ[X]
hp : (q * p).IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) (q * p) = 0 ∧ (aeval z) (q * p).mirror = 0)
hq' : q ∣ (q * p).mirror
⊢ IsUnit q

tactic: replace hp := hp.leadingCoeff_isUnit
state_before: case intro
q✝ q : ℤ[X]
this : ¬0 < q.natDegree
p : ℤ[X]
hp : (q * p).IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) (q * p) = 0 ∧ (aeval z) (q * p).mirror = 0)
hq' : q ∣ (q * p).mirror
⊢ IsUnit q
state_after: case intro
q✝ q : ℤ[X]
this : ¬0 < q.natDegree
p : ℤ[X]
h : ∀ (z : ℂ), ¬((aeval z) (q * p) = 0 ∧ (aeval z) (q * p).mirror = 0)
hq' : q ∣ (q * p).mirror
hp : IsUnit (q * p).leadingCoeff
⊢ IsUnit q

tactic: rw [leadingCoeff_mul] at hp
state_before: case intro
q✝ q : ℤ[X]
this : ¬0 < q.natDegree
p : ℤ[X]
h : ∀ (z : ℂ), ¬((aeval z) (q * p) = 0 ∧ (aeval z) (q * p).mirror = 0)
hq' : q ∣ (q * p).mirror
hp : IsUnit (q * p).leadingCoeff
⊢ IsUnit q
state_after: case intro
q✝ q : ℤ[X]
this : ¬0 < q.natDegree
p : ℤ[X]
h : ∀ (z : ℂ), ¬((aeval z) (q * p) = 0 ∧ (aeval z) (q * p).mirror = 0)
hq' : q ∣ (q * p).mirror
hp : IsUnit (q.leadingCoeff * p.leadingCoeff)
⊢ IsUnit q

tactic: replace hp := isUnit_of_mul_isUnit_left hp
state_before: case intro
q✝ q : ℤ[X]
this : ¬0 < q.natDegree
p : ℤ[X]
h : ∀ (z : ℂ), ¬((aeval z) (q * p) = 0 ∧ (aeval z) (q * p).mirror = 0)
hq' : q ∣ (q * p).mirror
hp : IsUnit (q.leadingCoeff * p.leadingCoeff)
⊢ IsUnit q
state_after: case intro
q✝ q : ℤ[X]
this : ¬0 < q.natDegree
p : ℤ[X]
h : ∀ (z : ℂ), ¬((aeval z) (q * p) = 0 ∧ (aeval z) (q * p).mirror = 0)
hq' : q ∣ (q * p).mirror
hp : IsUnit q.leadingCoeff
⊢ IsUnit q

tactic: rw [not_lt, Nat.le_zero] at this
state_before: case intro
q✝ q : ℤ[X]
this : ¬0 < q.natDegree
p : ℤ[X]
h : ∀ (z : ℂ), ¬((aeval z) (q * p) = 0 ∧ (aeval z) (q * p).mirror = 0)
hq' : q ∣ (q * p).mirror
hp : IsUnit q.leadingCoeff
⊢ IsUnit q
state_after: case intro
q✝ q : ℤ[X]
this : q.natDegree = 0
p : ℤ[X]
h : ∀ (z : ℂ), ¬((aeval z) (q * p) = 0 ∧ (aeval z) (q * p).mirror = 0)
hq' : q ∣ (q * p).mirror
hp : IsUnit q.leadingCoeff
⊢ IsUnit q

tactic: rwa [eq_C_of_natDegree_eq_zero this, isUnit_C, ← this]
state_before: case intro
q✝ q : ℤ[X]
this : q.natDegree = 0
p : ℤ[X]
h : ∀ (z : ℂ), ¬((aeval z) (q * p) = 0 ∧ (aeval z) (q * p).mirror = 0)
hq' : q ∣ (q * p).mirror
hp : IsUnit q.leadingCoeff
⊢ IsUnit q
state_after: no goals

tactic: cases' hq with g' hg'
state_before: case intro.refine_1
p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
hq'' : 0 < (map (algebraMap ℤ ℂ) q).degree
z : ℂ
hz : (aeval z) q = 0
⊢ (aeval z) p = 0
state_after: case intro.refine_1.intro
p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq' : q ∣ p.mirror
hq'' : 0 < (map (algebraMap ℤ ℂ) q).degree
z : ℂ
hz : (aeval z) q = 0
g' : ℤ[X]
hg' : p = q * g'
⊢ (aeval z) p = 0

tactic: rw [hg', aeval_mul, hz, zero_mul]
state_before: case intro.refine_1.intro
p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq' : q ∣ p.mirror
hq'' : 0 < (map (algebraMap ℤ ℂ) q).degree
z : ℂ
hz : (aeval z) q = 0
g' : ℤ[X]
hg' : p = q * g'
⊢ (aeval z) p = 0
state_after: no goals

tactic: cases' hq' with g' hg'
state_before: case intro.refine_2
p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq' : q ∣ p.mirror
hq'' : 0 < (map (algebraMap ℤ ℂ) q).degree
z : ℂ
hz : (aeval z) q = 0
⊢ (aeval z) p.mirror = 0
state_after: case intro.refine_2.intro
p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq'' : 0 < (map (algebraMap ℤ ℂ) q).degree
z : ℂ
hz : (aeval z) q = 0
g' : ℤ[X]
hg' : p.mirror = q * g'
⊢ (aeval z) p.mirror = 0

tactic: rw [hg', aeval_mul, hz, zero_mul]
state_before: case intro.refine_2.intro
p q✝ : ℤ[X]
hp : p.IsUnitTrinomial
h : ∀ (z : ℂ), ¬((aeval z) p = 0 ∧ (aeval z) p.mirror = 0)
q : ℤ[X]
hq : q ∣ p
hq'' : 0 < (map (algebraMap ℤ ℂ) q).degree
z : ℂ
hz : (aeval z) q = 0
g' : ℤ[X]
hg' : p.mirror = q * g'
⊢ (aeval z) p.mirror = 0
state_after: no goals