proposition: Lemma map_mx_unit n' (A : 'M_n'.+1) : (A^f \is a GRing.unit) = (A \is a GRing.unit).
proof: Proof. exact: map_unitmx. 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)