(* Permutation matrix *)

Definition perm_mx n s : 'M_n := row_perm s 1%:M.Definition tperm_mx n i1 i2 : 'M_n := perm_mx (tperm i1 i2).

Lemma row_permE m n s (A : 'M_(m, n)) : row_perm s A = perm_mx s *m A.