proposition: Lemma mx_root_minpoly : horner_mx A p_A = 0.
proof: Proof. rewrite rmorphB -{3}(horner_mx_X A) -rmorphXn /=. by rewrite mx_inv_hornerK ?subrr ?horner_mx_mem. 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)