proposition: Lemma map_poly_com p x : comm_poly p^f (f x).
proof: Proof. exact: map_comm_poly (mulrC x _). Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)