proposition: Lemma gamma_step_list: forall (g : Graph) x d l r, vvalid g x -> vgamma g x = (d, l, r) -> step_list g x (l :: r :: nil).
proof: Proof. intros. unfold step_list. intros y. rewrite gamma_step by eauto. simpl. pose proof (@eq_sym _ l y). pose proof (@eq_sym _ r y). pose proof (@eq_sym _ y l). pose proof (@eq_sym _ y r). tauto. Qed.
imports: CertiGraph.lib.Ensembles_ext Coq.Lists.List VST.msl.seplog VST.msl.log_normalize CertiGraph.lib.Coqlib CertiGraph.lib.EquivDec_ext CertiGraph.msl_ext.log_normalize CertiGraph.msl_ext.iter_sepcon CertiGraph.msl_ext.seplog CertiGraph.graph.graph_model CertiGraph.graph.path_lemmas CertiGraph.graph.reachable_computable CertiGraph.graph.reachable_ind CertiGraph.graph.subgraph2 CertiGraph.graph.graph_gen CertiGraph.graph.BinGraph CertiGraph.graph.MathGraph CertiGraph.graph.FiniteGraph CertiGraph.msl_application.Graph Coq.Logic.Classical