fact: Definition ZFS_elementof (X Y : ZFS) := ∑ (a : Y), (isapoint a) × (X = Y ↑ a).
imports: UniMath.Foundations.PartB UniMath.Foundations.Propositions UniMath.Foundations.Sets UniMath.Foundations.HLevels UniMath.Combinatorics.WellOrderedSets UniMath.Combinatorics.OrderedSets UniMath.MoreFoundations.DecidablePropositions UniMath.MoreFoundations.Propositions