proposition: Lemma split_list_In: forall (l: list V) v, In v l -> exists la lb, l = la ++ v::lb.
proof: Proof. intros. apply split_list_In_first in H. destruct H as [la [lb [? ?]]]. exists la; exists lb; apply 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