proposition: Lemma scalemx_add : forall n a1 a2, @scalar_mx n (a1 + a2) === a1%:M +m a2%:M.
proof: Proof. by move=> n a1 a2 i j; rewrite/scalar_mx/addmx; case: (i==j); ring. Qed.
imports: ssreflect ssrbool ssrfun eqtype ssrnat seq choice fintype finfun bigops ssralg groups perm zmodp morphisms Ring RingClass bigopsClass Setoid Morphisms