proposition: Lemma isOpen_htrue : isOpen (λ _ : T, htrue).
proof: Proof. rewrite <- finite_intersection_htrue. apply isOpen_finite_intersection. intros m. induction (nopathsfalsetotrue (pr2 m)). Qed.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.Topology.Filters UniMath.Algebra.Groups UniMath.Algebra.DivisionRig UniMath.Algebra.ConstructiveStructures