proposition: Lemma rVpolyK : cancel rVpoly poly_rV.
proof: Proof. by move=> u; apply/rowP=> i; rewrite mxE coef_rVpoly_ord. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(div fintype tuple finfun bigop fingroup perm) mathcomp(ssralg zmodp matrix mxalgebra poly polydiv)