proposition: Lemma lin_mul_row_is_linear : linear lin_mul_row.
proof: Proof. move=> a u v; apply/row_matrixP=> i; rewrite linearP /= !rowE !mul_rV_lin1 /=. by rewrite [_ *m _](linearP (mulmxr (_ : 'M[R]__))). 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)