proposition: Fact poly_mulVp : {in poly_unit, left_inverse 1 poly_inv *%R}.
proof: Proof. move=> p Up; rewrite /poly_inv Up. by case/andP: Up => /size_poly1P[c _ ->]; rewrite coefC -polyCM => /mulVr->. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)