proposition: Lemma rscalp_small p q : size p < size q -> rscalp p q = 0.
proof: Proof. rewrite /rscalp unlock; case: eqP => _ // spq. by case sp: (size p) => [| s] /=; rewrite spq. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop ssralg poly)