proposition: Lemma rowsub_comp_sub (m n p q : nat) f (g : 'I_n -> 'I_p) (A : 'M_(m, q)) : (rowsub (f \o g) A <= rowsub f A)%MS.
proof: Proof. by rewrite rowsub_comp 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)