proposition: Lemma normr_idP {x} : reflect (`|x| = x) (0 <= x).
proof: Proof. by rewrite ger0_def; apply: eqP. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)