proposition: Lemma rVpoly_delta i : rVpoly (delta_mx 0 i) = 'X^i.
proof: Proof. apply/polyP=> j; rewrite coef_rVpoly coefXn. case: insubP => [k _ <- | j_ge_d]; first by rewrite mxE. by case: eqP j_ge_d => // ->; rewrite ltn_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)