fact: Definition finite_singleton_is_in {X : hSet} (A : hsubtype X) (a : A) : finite_singleton (pr1 a) ⊆ A.
imports: UniMath.MoreFoundations.Tactics UniMath.MoreFoundations.DecidablePropositions UniMath.MoreFoundations.NegativePropositions UniMath.Combinatorics.StandardFiniteSets UniMath.MoreFoundations.Subtypes