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