proposition: Lemma det_line_scale : forall n k a (M: 'M[R]_n), \det (line_scale k a M) = a * \det M.
proof: Proof. move => n k a M. by rewrite line_scale_eq det_line_scale_mx. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(ssralg fintype perm choice) mathcomp(matrix bigop zmodp mxalgebra poly mxpoly)