proposition: Fact scale_1poly : left_id 1 scale_poly.
proof: Proof. by move=> p; rewrite scale_polyE mul1r. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)