proposition: Lemma map_polyK (f : aR -> rR) g : cancel g f -> f 0 = 0 -> cancel (map_poly g) (map_poly f).
proof: Proof. by move=> gK f_0 p; rewrite /= -map_poly_comp_id0 ?map_poly_id // => x _ //=. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)