CPT- and Lorentz-Transformations in Two-Dimensional Q.F.T.

The C.P.T.-theorem plays an important role in relativistic quantum field theory. In 1957 R.Jost [3] gave a proof of the C.P.T.-theorem in the frame of Wightman-field theory in which he revealed the connection of the C.P.T.-symmetry with the assumptions of positivity of the energy, Lorentz-invariance, and the standard locality assumptions. In this proof the existence of a vacuum state was essential. But up to now there is no proof of the C.P.T.-theorem in the theory of local observables in the sense of Araki, Haag, and Kastler.