proposition: Lemma swapXY_poly_XaY p : swapXY (poly_XaY p) = poly_XaY p.
proof: Proof. by rewrite swapXY_comp_poly rmorphD /= swapXY_X swapXY_Y addrC. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype choice ssrnat seq) mathcomp(fintype tuple finfun bigop fingroup perm div) mathcomp(ssralg zmodp matrix mxalgebra) mathcomp(poly polydiv mxpoly binomial)