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