proposition: Lemma ang_graph_has_v_inv: forall g gi v, number_of_vertices gi = O -> graph_has_v (lgraph_add_new_gen g gi) v -> graph_has_v g v.
proof: Proof. intros. destruct v as [gen idx]. destruct H0; split; simpl in *. - apply ang_graph_has_gen in H0. destruct H0; auto. red in H1. exfalso. subst. rewrite ang_nth_new, H in H1. lia. - apply ang_graph_has_gen in H0. red in H1. destruct H0. + rewrite ang_nth_old in H1; assumption. + exfalso. subst. rewrite ang_nth_new, H in H1. lia. Qed.
imports: Coq.ZArith.ZArith Coq.Program.Basics Coq.micromega.Lia 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 VST.zlist.list_solver CertiGraph.lib.EquivDec_ext CertiGraph.lib.List_ext CertiGraph.graph.graph_model CertiGraph.graph.graph_gen