∀ {α : Type u} {β : Type v} {γ : Type w} [inst : Preorder α] [inst_1 : Preorder β] [inst_2 : Preorder γ] {f : α → β → γ}
  {s : Set α} {t : Set β},
  (∀ (b : β), Antitone (Function.swap f b)) →
    (∀ (a : α), Monotone (f a)) → BddBelow s → BddAbove t → BddAbove (Set.image2 f s t)