fact: Definition diag_mx_seq m n (s : seq R) := \matrix_(i < m, j < n) (s`_i *+ (i == j :> nat)).
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq path) mathcomp(ssralg fintype perm poly mxpoly finfun tuple) mathcomp(matrix bigop zmodp polydiv) ssrcomplements dvdring