fact: Definition isfinitedecsubset {X : UU} (f : X -> bool) (sx : isfinite X) : isfinite (hfiber f true) := hinhfun (finstructondecsubset f) sx.
imports: UniMath.MoreFoundations.Tactics UniMath.MoreFoundations.DecidablePropositions UniMath.MoreFoundations.NegativePropositions UniMath.Combinatorics.StandardFiniteSets UniMath.MoreFoundations.Subtypes