Section set_together_def.
Variables (f : Map C A) (g : Map C B).
Definition S_together_fun (c : C) := Build_Sprod (f c) (g c).
Definition S_together := Build_Map S_together_map_law.
End set_together_def.
(* ve'rification des lois *)

Lemma S_together_r : Map2_congr_law S_together.