proposition: Lemma npoly_rV_K : cancel npoly_rV rVnpoly.
proof: Proof. move=> p /=; apply/val_inj. by rewrite val_insubd [_ \is a _]size_poly ?poly_rV_K. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice fintype tuple) mathcomp(bigop binomial finset finfun ssralg countalg finalg poly polydiv) mathcomp(perm fingroup matrix mxalgebra mxpoly vector countalg)