exact ha₁
case intro.refine_2.inl.intro.refine_1.refine_2.h
R : Type u_1
inst✝ : CancelCommMonoidWithZero R
m : Multiset R
a✝¹ : R
s : Multiset R
hind :
  ∀ (a b : R),
    a * b ∈ closure {r | IsUnit r ∨ Prime r} →
      (∀ y ∈ s, y ∈ {r | IsUnit r ∨ Prime r}) → Multiset.prod s = a * b → a ∈ closure {r | IsUnit r ∨ Prime r}
x y : R
a✝ : x * y ∈ closure {r | IsUnit r ∨ Prime r}
hs : ∀ y ∈ s, y ∈ {r | IsUnit r ∨ Prime r}
hprod : a✝¹ * Multiset.prod s = x * y
ha₁ : IsUnit a✝¹
k : R
hk : a✝¹ * k = 1
⊢ IsUnit a✝¹

case intro.refine_2.inl.intro.refine_2
R : Type u_1
inst✝ : CancelCommMonoidWithZero R
m : Multiset R
a✝¹ : R
s : Multiset R
hind :
  ∀ (a b : R),
    a * b ∈ closure {r | IsUnit r ∨ Prime r} →
      (∀ y ∈ s, y ∈ {r | IsUnit r ∨ Prime r}) → Multiset.prod s = a * b → a ∈ closure {r | IsUnit r ∨ Prime r}
x y : R
a✝ : x * y ∈ closure {r | IsUnit r ∨ Prime r}
hs : ∀ y ∈ s, y ∈ {r | IsUnit r ∨ Prime r}
hprod : a✝¹ * Multiset.prod s = x * y
ha₁ : IsUnit a✝¹
k : R
hk : a✝¹ * k = 1
⊢ Multiset.prod s = x * (y * k)
case intro.refine_2.inl.intro.refine_2
R : Type u_1
inst✝ : CancelCommMonoidWithZero R
m : Multiset R
a✝¹ : R
s : Multiset R
hind :
  ∀ (a b : R),
    a * b ∈ closure {r | IsUnit r ∨ Prime r} →
      (∀ y ∈ s, y ∈ {r | IsUnit r ∨ Prime r}) → Multiset.prod s = a * b → a ∈ closure {r | IsUnit r ∨ Prime r}
x y : R
a✝ : x * y ∈ closure {r | IsUnit r ∨ Prime r}
hs : ∀ y ∈ s, y ∈ {r | IsUnit r ∨ Prime r}
hprod : a✝¹ * Multiset.prod s = x * y
ha₁ : IsUnit a✝¹
k : R
hk : a✝¹ * k = 1
⊢ Multiset.prod s = x * (y * k)