proposition: Lemma ngr_no_dangling_dst: forall g1 g2 gen, no_dangling_dst g1 -> new_gen_relation gen g1 g2 -> no_dangling_dst g2.
proof: Proof. intros. red in H0. destruct (graph_has_gen_dec g1 gen). - subst; auto. - destruct H0 as [gen_i [? ?]]. subst g2. unfold no_dangling_dst in *. intros. simpl in *. apply ang_graph_has_v_inv in H1; auto. apply ang_graph_has_v. rewrite <- ang_get_edges in H2. eapply H; eauto. Qed.
imports: Coq.ZArith.ZArith Coq.Program.Basics compcert.lib.Integers compcert.common.Values VST.veric.base VST.veric.Clight_lemmas VST.veric.val_lemmas VST.veric.shares VST.msl.seplog VST.msl.shares VST.zlist.sublist VST.floyd.coqlib3 VST.floyd.functional_base VST.floyd.data_at_rec_lemmas CertiGraph.lib.Coqlib CertiGraph.lib.EquivDec_ext CertiGraph.lib.List_ext CertiGraph.graph.graph_model CertiGraph.graph.graph_gen CertiGraph.graph.path_lemmas CertiGraph.graph.subgraph2 CertiGraph.graph.graph_relation CertiGraph.graph.graph_isomorphism CertiGraph.graph.reachable_ind CertiGraph.CertiGC.GCGraph