proposition: Lemma in_edge_func_edge: forall root x, In x (filter not_null_bool (map (dst G) (edge_func G root))) <-> G |= root ~> x.
proof: Proof. intros. apply in_step_list_edge. intro. rewrite edge_func_step. tauto. Qed.
imports: Coq.Arith.Arith CertiGraph.lib.Coqlib CertiGraph.lib.EnumEnsembles CertiGraph.lib.EquivDec_ext CertiGraph.lib.List_ext CertiGraph.graph.graph_model CertiGraph.graph.path_lemmas CertiGraph.graph.subgraph2 CertiGraph.graph.MathGraph CertiGraph.graph.FiniteGraph CertiGraph.graph.reachable_computable Coq.Lists.List