proposition: Lemma normr0P v : reflect (`|v| = 0) (v == 0).
proof: Proof. by apply: (iffP eqP)=> [->|/normr0_eq0 //]; apply: normr0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)