proposition: Corollary fun_comp_assoc {C D E B : Category} {F : E ⟶ B} {G : D ⟶ E} {H : C ⟶ D} : F ◯ (G ◯ H) ⟹ (F ◯ G) ◯ H.
proof: Proof. transform; simpl; intros; cat. Defined.
imports: Category.Lib Category.Theory.Category Category.Theory.Functor