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