fact: Definition respectful_set {A B: Type} (X: Ensemble B) (f: A -> B): Ensemble A := fun x => X (f x).
imports: Coq.Classes.Morphisms Coq.Classes.Equivalence Coq.Sets.Ensembles Coq.Sets.Constructive_sets CertiGraph.lib.Coqlib CertiGraph.lib.EquivDec_ext