proposition: Lemma cofactor_map_mx (A : 'M_n) i j : cofactor A^f i j = f (cofactor A i j).
proof: Proof. by rewrite rmorphM /= rmorph_sign -det_map_mx map_row' map_col'. 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)