proposition: Corollary fork_inv {x y z : C} (f h : x ~> y) (g i : x ~> z) : f △ g ≈ h △ i ↔ f ≈ h ∧ g ≈ i.
proof: Proof. pose proof (ump_products h i (f △ g)) as HA; simplify; intuition. - now rewrite exl_fork in a. - now rewrite exr_fork in b. - apply X0; cat. Qed.
imports: Category.Lib Category.Theory.Category Category.Theory.Isomorphism Category.Structure.Terminal