proposition: Lemma row_subPn m1 m2 n (A : 'M_(m1, n)) (B : 'M_(m2, n)) : reflect (exists i, ~~ (row i A <= B)%MS) (~~ (A <= B)%MS).
proof: Proof. by rewrite (sameP row_subP forallP); apply: forallPn. 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)