fact: Definition nelstructonempty2 {X : UU} (nx : neg X) : nelstruct 0 X := weqcomp weqstn0toempty (invweq (weqtoempty nx)).
imports: UniMath.MoreFoundations.Tactics UniMath.MoreFoundations.DecidablePropositions UniMath.MoreFoundations.NegativePropositions UniMath.Combinatorics.StandardFiniteSets UniMath.MoreFoundations.Subtypes