proposition: Lemma real_leif_norm x : x \is real -> x <= `|x| ?= iff (0 <= x).
proof: Proof. by move=> xR; rewrite ger0_def eq_sym; apply: leif_eq; rewrite real_ler_norm. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)