proposition: Lemma step_vvalid: forall g s t, sound_gc_graph g -> no_dangling_dst g -> step g s t -> vvalid g t.
proof: Proof. intros. destruct H as [? [? [? Hels]]]. red in H, H0, H2, H3. rewrite step_spec in H1. destruct H1 as [e [? [? ?]]]. rewrite <- H5, H. rewrite H2 in H1. destruct H1. now apply (H0 (fst e)). 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