Theorem: ℤθ.my_zero_mul (Mordell4/CubicRing.lean)

State before:
a b c : ℤθ
⊢ mul zero a = zero
Tactic:
cases a
State after:
case mk
b c : ℤθ
f✝ g✝ h✝ : ℤ
⊢ mul zero { f := f✝, g := g✝, h := h✝ } = zero

State before:
case mk
b c : ℤθ
f✝ g✝ h✝ : ℤ
⊢ mul zero { f := f✝, g := g✝, h := h✝ } = zero
Tactic:
simp [mul, zero]
State after:
no goals