proposition: Lemma scale_addid (x: R) m n (I : 'cV[R]_m) (J: 'cV[R]_n): x *: (I +i J) = (x *: I) +i (x *: J).
proof: Proof. by rewrite /addid -scale_col_mx. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq path) mathcomp(ssralg fintype perm choice fingroup) mathcomp(matrix bigop zmodp mxalgebra poly) ssrcomplements