proposition: Corollary valid_upath_tail: forall g p, valid_upath g p -> valid_upath g (tl p).
proof: Proof. intros; destruct p. auto. simpl. apply (valid_upath_tail' g p v H). 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