fact: Definition graph_is_acyclic (g: Gph) : Prop := forall p : path, valid_path g p -> NoDup (epath_to_vpath g p).
imports: Coq.Logic.ProofIrrelevance Coq.micromega.Lia CertiGraph.lib.Coqlib CertiGraph.lib.EnumEnsembles CertiGraph.lib.List_ext CertiGraph.lib.EquivDec_ext CertiGraph.graph.graph_model Coq.Lists.List Coq.Lists.ListDec