End CGAdd.
(*s Properties of the range of the graph *)
Definition cg_range := DMerge D.

Lemma cg_out_of_range_3 :
forall (cg : CGraph1) (y : ad),
in_dom D y (cg_range cg) = false ->
forall x : ad, Neqb x y = false -> CG_leq cg x y = false.