proposition: Lemma map_mxD A B : (A + B)^f = A^f + B^f.
proof: Proof. by apply/matrixP=> i j; rewrite !mxE raddfD. 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 countalg finalg zmodp)