Derivations and Automorphisms on the Algebra of Non-commutative Power Series

<Motivated by the study of multiple zeta values, we discuss several linear operators on the algebra of non-commutative formal power series k<<x,y>> over a field k of characteristic zero. Especially a family of derivations whose elements commute with each other is defined and automorphisms which correspond to these derivations via exponential map are described explicitly./p>