proposition: Lemma polyseq0 : (0 : {poly R}) = [::] :> seq R.
proof: Proof. by rewrite polyseqC eqxx. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)