∀ {α : Type u_2} {β : Type u_3} [inst : Preorder α] [inst_1 : BoundedOrder α] [inst_2 : Preorder β]
  [inst_3 : BoundedOrder β] (f : BoundedOrderHom αᵒᵈ βᵒᵈ),
  (BoundedOrderHom.dual.symm f).toOrderHom = OrderHom.dual.symm f.toOrderHom