proposition: Lemma drop_polyD m p q : drop_poly m (p + q) = drop_poly m p + drop_poly m q.
proof: Proof. by apply/polyP => i; rewrite coefD !coef_drop_poly coefD. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)