proposition: Lemma BaseOfFilter_notempty {X : UU} (base : BaseOfFilter X) : ∃ A : X → hProp, base A.
proof: Proof. apply (pr1 (pr2 (pr2 base))). Qed.
imports: UniMath.Foundations.Preamble UniMath.MoreFoundations.Tactics UniMath.Topology.Prelim UniMath.MoreFoundations.PartA