fact: Definition filternat : (nat → hProp) → hProp := λ P : nat → hProp, ∃ N : nat, ∏ n : nat, N ≤ n → P n.
imports: UniMath.Foundations.Preamble UniMath.MoreFoundations.Tactics UniMath.Topology.Prelim UniMath.MoreFoundations.PartA