proposition: Corollary edgeless_GG_numE: numE edgeless_GG = 0.
proof: Proof. unfold numE. rewrite edgeless_GG_EList. apply Zlength_nil. Qed.
imports: VST.floyd.proofauto CertiGraph.lib.Coqlib CertiGraph.lib.EquivDec_ext CertiGraph.lib.List_ext CertiGraph.graph.graph_model CertiGraph.graph.graph_gen CertiGraph.graph.FiniteGraph CertiGraph.graph.undirected_graph