proposition: Lemma row_base_free m n (A : 'M_(m, n)) : row_free (row_base A).
proof: Proof. by apply/eqnP; rewrite eq_row_base. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype finfun bigop finset fingroup perm order) mathcomp(div prime binomial ssralg finalg zmodp matrix)