proposition: Lemma coef_cons c p i : (cons_poly c p)`_i = if i == 0 then c else p`_i.-1.
proof: Proof. by case: p i => [[|c' s] _] [] //=; rewrite polyseqC; case: eqP => //= _ []. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)