fact: Definition pr1LeastUpperBound {E : hsubtype X} : LeastUpperBound E → X := pr1.
imports: UniMath.Foundations.Sets UniMath.MoreFoundations.QuotientSet UniMath.MoreFoundations.Tactics UniMath.MoreFoundations.Sets UniMath.MoreFoundations.Orders UniMath.Algebra.BinaryOperations UniMath.Algebra.Apartness UniMath.OrderTheory.Lattice.Lattice