proposition: Lemma isrefl_filter_le {X : UU} : ∏ F : PreFilter X, filter_le F F.
proof: Proof. intros F A Fa. exact Fa. Qed.
imports: UniMath.Foundations.Preamble UniMath.MoreFoundations.Tactics UniMath.Topology.Prelim UniMath.MoreFoundations.PartA