proposition: Lemma row_sub m n i (A : 'M_(m, n)) : (row i A <= A)%MS.
proof: Proof. exact: rowsub_sub. 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)