∀ {α : Type u_2} {β : Type u_3} [inst : CommMonoid α] [inst_1 : CommMonoid β] {A : Set α} {B : Set β} {f : α → β},
  IsMulFreimanIso 2 A B f → ∀ {a b c d : α}, a ∈ A → b ∈ A → c ∈ A → d ∈ A → (f a * f b = f c * f d ↔ a * b = c * d)