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