fact: Definition normrE := (normr_id, normr0, normr1, normrN1, normr_ge0, normr_eq0, normr_lt0, normr_le0, normr_gt0, normrN).
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)