proposition: Lemma lteif_nnormr C x y : y < 0 ?<= if ~~ C -> (`|x| < y ?<= if C) = false.
proof: Proof. by case: C => ?; rewrite /= lter_nnormr. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)