proposition: Lemma ger0_norm x : 0 <= x -> `|x| = x.
proof: Proof. exact: normr_idP. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)