no goals
R : Type u
S : Type v
a b c d : R
n m : ℕ
inst✝ : Semiring R
p q : R[X]
ι : Type ?u.659713
h : leadingCoeff p * leadingCoeff q ≠ 0
h₁ : leadingCoeff p = 0
⊢ leadingCoeff p * leadingCoeff q = 0
rw [h₁, zero_mul]
no goals
R : Type u
S : Type v
a b c d : R
n m : ℕ
inst✝ : Semiring R
p q : R[X]
ι : Type ?u.659713
h : leadingCoeff p * leadingCoeff q ≠ 0
hp : p ≠ 0
h₁ : leadingCoeff q = 0
⊢ leadingCoeff p * leadingCoeff q = 0
rw [h₁, mul_zero]
no goals
R : Type u
S : Type v
a b c d : R
n m : ℕ
inst✝ : Semiring R
p q : R[X]
ι : Type ?u.659713
h : leadingCoeff p * leadingCoeff q ≠ 0
hp : p ≠ 0
hq : q ≠ 0
⊢ degree (p * q) = ↑(natDegree p + natDegree q)
rw [degree_mul' h, Nat.cast_withBot, WithBot.coe_add, degree_eq_natDegree hp,
  degree_eq_natDegree hq, ← Nat.cast_withBot, ← Nat.cast_withBot]