proposition: Lemma sgz_odd (n : nat) x : x != 0 -> (sgz x) ^+ n = (sgz x) ^+ (odd n).
proof: Proof. by case: sgzP => //=; rewrite ?expr1n // signr_odd. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)