exact isUnit_of_mul_eq_one _ _ hprod.2.symm
case intro.refine_1.h
R : Type u_1
inst✝ : CancelCommMonoidWithZero R
m : Multiset R
x✝² x✝¹ : R
x✝ : x✝² * x✝¹ ∈ closure {r | IsUnit r ∨ Prime r}
hprod : ∃ (_ : ∀ y ∈ 0, y ∈ {r | IsUnit r ∨ Prime r}), Multiset.prod 0 = x✝² * x✝¹
⊢ IsUnit x✝²
no goals