proposition: Corollary connected_trans: forall g u v w, connected g u v -> connected g v w -> connected g u w.
proof: Proof. intros. destruct H as [p1 ?]. destruct H0 as [p2 ?]. exists (p1++(tail p2)). apply (connected_by_path_join g p1 p2 u v w); 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