proposition: Lemma dvd_col_mxu m0 m1 m2 (M : 'M[R]_(m0, m2)) (N : 'M_(m1, m2)) : col_mx M N %| M.
proof: Proof. by apply/dvd_col_mxP; exists 0; rewrite mul0mx subr0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq path) mathcomp(ssralg fintype perm choice matrix bigop zmodp mxalgebra poly) ssrcomplements dvdring stronglydiscrete