proposition: Lemma capTmx m1 m2 n (A : 'M_(m1, n)) (B : 'M_(m2, n)) : row_full A -> (A :&: B :=: B)%MS.
proof: Proof. by move=> Afull; apply/eqmxP; rewrite capmxC !capmxT ?andbb. 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)