proposition: Lemma map_diffmx m1 m2 n (A : 'M_(m1, n)) (B : 'M_(m2, n)) : ((A :\: B)^f :=: A^f :\: B^f)%MS.
proof: Proof. apply/eqmxP; rewrite !diffmxE -map_capmx_gen -map_complmx. by rewrite -!map_capmx !map_submx -!diffmxE 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)