Section CGAdd.
Variable cg1 : CGraph1.
Variable x y : ad.
Variable d : D.
Definition cg2 := CG_add cg1 x y d.

Lemma CG_add_edge_2 :
forall x0 y0 : ad, Ddle (CG_edge cg2 x0 y0) (CG_edge cg1 x0 y0) = true.