fact: Definition least_upper_bound_in_subposet {P : Poset} {A : Subposet P} {I} {p : I -> A} (x : least_upper_bound (pr1 ∘ p)) (x_A : A x) : least_upper_bound p.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.Combinatorics.WellOrderedSets UniMath.OrderTheory.DCPOs.AlternativeDefinitions.Dcpo