proposition: Lemma lc_expn_scalp_neq0 p q : lead_coef q ^+ scalp p q != 0.
proof: Proof. have [->|nzq] := eqVneq q 0; last by rewrite expf_neq0 ?lead_coef_eq0. by rewrite /scalp 2!unlock /= eqxx lead_coef0 unitr0 /= oner_neq0. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop ssralg poly)