proposition: Lemma valid_path'_cons: forall (g: PreGraph V E) p a, valid_path' g (a::p) -> valid_path' g p.
proof: Proof. intros; destruct p. reflexivity. simpl. simpl in H. destruct H. destruct H0. apply H1. Qed.
imports: Coq.Logic.Classical CertiGraph.lib.List_ext CertiGraph.lib.EquivDec_ext CertiGraph.graph.graph_model CertiGraph.graph.graph_relation CertiGraph.graph.path_lemmas CertiGraph.graph.graph_gen CertiGraph.graph.FiniteGraph