fact: Definition isbase_and := ∏ A B : X → hProp, base A → base B → ∃ C : X → hProp, base C × (∏ x, C x → A x ∧ B x).
imports: UniMath.Foundations.Preamble UniMath.MoreFoundations.Tactics UniMath.Topology.Prelim UniMath.MoreFoundations.PartA