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

Lemma CG_add_1 :
forall rho : ad -> D,
CGsat cg1 rho -> Dle (rho x) (Dplus (rho y) d) = true -> CGsat cg2 rho.