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