proposition: Lemma istrans_filter_le {X : UU} : ∏ F G H : PreFilter X, filter_le F G → filter_le G H → filter_le F H.
proof: Proof. intros F G H Hfg Hgh A Fa. apply Hfg, Hgh, Fa. Qed.
imports: UniMath.Foundations.Preamble UniMath.MoreFoundations.Tactics UniMath.Topology.Prelim UniMath.MoreFoundations.PartA