Definition FilterNat : Filter nat. Proof. simple refine (make_Filter _ _ _ _ _). - apply filternat. - apply filternat_imply. - apply filternat_htrue. - apply filternat_and. - apply filternat_notempty. Defined.
Require Import UniMath.Foundations.Preamble. Require Import UniMath.MoreFoundations.Tactics. Require Import UniMath.MoreFoundations.PartA.