fact: Definition to_list {A} (S : Ensemble A) : Comp (list A) := { ls : list _ | EnsembleListEquivalence S ls }.
imports: Coq.Lists.List Coq.Sets.Ensembles Fiat.Computation.Core Fiat.Computation.Notations Fiat.Common.Ensembles.EnsembleListEquivalence Fiat.Common.Ensembles.Cardinal