fact: Definition subsetFiniteSet {X : FiniteSet} (P : DecidableSubtype X) : FiniteSet.
imports: UniMath.MoreFoundations.Tactics UniMath.MoreFoundations.DecidablePropositions UniMath.MoreFoundations.NegativePropositions UniMath.Combinatorics.StandardFiniteSets UniMath.MoreFoundations.Subtypes