proposition: Lemma ler_normr x y : (x <= `|y|) = (x <= y) || (x <= - y).
proof: Proof. exact: real_ler_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)