Section com_arrow_def.
Variable axf bxg : Com_ob.
Definition Com_law (h : Ob_com_ob axf --> Ob_com_ob bxg) :=
Mor_com_ob bxg =_S Mor_com_ob axf o FMor G h.
Structure > Com_arrow : Type :=
{Mor_com_arrow : Ob_com_ob axf --> Ob_com_ob bxg;
Prf_com_law :> Com_law Mor_com_arrow}.
(*** rewrite rules ***)
(* *)
Definition Equal_com_arrow (h h' : Com_arrow) :=
Mor_com_arrow h =_S Mor_com_arrow h'.

Lemma Equal_com_arrow_equiv : Equivalence Equal_com_arrow.