proposition: Lemma map_mxN A : (- A)^f = - A^f.
proof: Proof. by apply/matrixP=> i j; rewrite !mxE raddfN. 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)