fact: Definition char_poly_alt n (M: 'M[R]_(1 + n)) := Bareiss (char_poly_mx M : 'M[polydvd.poly_of R]__).
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq path) mathcomp(ssralg fintype perm choice) mathcomp(matrix bigop zmodp mxalgebra poly polydiv mxpoly) ssrcomplements dvdring minor atomic_operations polydvd