(* construire un Comp_Type *)

Definition Comp_Darrow (a b c : C) (df : DHom a b) (dg : DHom b c) := dg o df.

(* Specifications: *)
Lemma Comp_dual_congl : Congl_law Comp_Darrow.
Lemma Comp_dual_congr : Congr_law Comp_Darrow.