proposition: Lemma edgeless_graph_evalid: forall e, ~ evalid edgeless_graph e.
proof: Proof. intros. unfold edgeless_graph; simpl. auto. Qed.
imports: VST.floyd.proofauto CertiGraph.lib.EquivDec_ext CertiGraph.lib.List_ext CertiGraph.lib.find_lemmas CertiGraph.graph.graph_model CertiGraph.graph.graph_gen CertiGraph.graph.graph_relation CertiGraph.graph.undirected_graph CertiGraph.graph.MathAdjMatGraph