proposition: Lemma adjacent_dec: forall g u v, adjacent g u v \/ ~ adjacent g u v.
proof: Proof. intros. tauto. 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