proposition: Lemma connected_by_path_rev: forall g p u v, connected_by_path g p u v -> connected_by_path g (rev p) v u.
proof: Proof. intros. split. apply valid_upath_rev. apply H. destruct H as [? [? ?]]. split. rewrite rev_hd_last, rev_involutive; auto. rewrite <- rev_hd_last; auto. 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