proposition: Lemma dvdpE p q : p %| q = rdvdp p q.
proof: Proof. rewrite /dvdp modpE /rdvdp; case ulcq: (lead_coef p \in GRing.unit)=> //. rewrite -[in LHS]size_poly_eq0 size_scale ?size_poly_eq0 //. by rewrite invr_eq0 expf_neq0 //; apply: contraTneq ulcq => ->; rewrite unitr0. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop ssralg poly)