Section MinPoly.
Variables (F : fieldType) (n' : nat).
Local Notation n := n'.+1.
Variable A : 'M[F]_n.
Implicit Types p q : {poly F}.
Fact degree_mxminpoly_proof : exists d, \rank (powers_mx A d.+1) <= d.

Lemma minpoly_mx_ring : mxring Ad.
Definition mxminpoly := 'X^d - mx_inv_horner (A ^+ d).