proposition: Theorem split_fork {x y z w v : C} (f : y ~> w) (h : z ~> v) (g : x ~> y) (i : x ~> z): split f h ∘ g △ i ≈ (f ∘ g) △ (h ∘ i).
proof: Proof. unfork. Qed.
imports: Category.Lib Category.Theory.Category Category.Theory.Isomorphism Category.Structure.Terminal