proposition: Lemma connected_refl: forall g v, vvalid g v -> connected g v v.
proof: Proof. intros. exists (v::nil). split. simpl; auto. split; simpl; 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