rintro g - hg h
case h₁

⊢ ∀ {g : Multiset ℤ},
    (∀ (x : ℤ), x ∈ 0 → OddPrimeOrFour x) →
      (∀ (x : ℤ), x ∈ g → OddPrimeOrFour x) →
        Associated (Multiset.prod 0) (Multiset.prod g) → Multiset.Rel Associated 0 g
case h₁
g : Multiset ℤ
hg : ∀ (x : ℤ), x ∈ g → OddPrimeOrFour x
h : Associated (Multiset.prod 0) (Multiset.prod g)
⊢ Multiset.Rel Associated 0 g