fact: Definition topologysubtype := λ (x : ∑ x : T, dom x) (A : (∑ x0 : T, dom x0) → hProp), ∃ B : T → hProp, (B (pr1 x) × isOpen B) × (∏ y : ∑ x0 : T, dom x0, B (pr1 y) → A y).
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.Topology.Filters UniMath.Algebra.Groups UniMath.Algebra.DivisionRig UniMath.Algebra.ConstructiveStructures