proposition: Lemma polyCD : {morph polyC : a b / a + b}.
proof: Proof. by move=> a b; apply/polyP=> [[|i]]; rewrite coefD !coefC ?addr0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)