(* Epic <-> Surj *)

SubClass SET_Epic_law (A B : Setoid) (f : Map A B) := Epic_law f.SubClass SET_Monic_law (A B : Setoid) (f : Map A B) := Monic_law f.

Lemma Surj_epic : forall h : B -> A, Surj_law f h -> SET_Epic_law f.