proposition: Lemma unitmx_perm s : perm_mx s \in unitmx.
proof: Proof. by rewrite unitmxE det_perm unitrX ?unitrN ?unitr1. 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)