proposition: Lemma lc_expn_rscalp_neq0 (p q : {poly R}): lead_coef q ^+ rscalp p q != 0.
proof: Proof. have [->|nzq] := eqVneq q 0; last by rewrite expf_neq0 ?lead_coef_eq0. by rewrite /rscalp unlock /= eqxx /= expr0 oner_neq0. Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(ssrfun ssrbool eqtype ssrnat seq choice fintype) mathcomp(bigop order ssralg poly polydiv ssrnum zmodp) mathcomp(polyorder path interval ssrint)