proposition: Lemma rowsub_sub m1 m2 n (f : 'I_m2 -> 'I_m1) (A : 'M_(m1, n)) : (rowsub f A <= A)%MS.
proof: Proof. by rewrite rowsubE mulmx_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)