proposition: Lemma minpoly_mx_free : row_free Ad.
proof: Proof. have:= mxminpoly_nonconstant; rewrite /d; case: ex_minnP => -[] // d' _ /(_ d'). by move/implyP; rewrite ltnn implybF -ltnS ltn_neqAle rank_leq_row andbT negbK. 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)