Generalized Haag's Theorem in SO(1,1) and SO(1,3) Invariant Quantum   Field Theory
  One of the most important results of the axiomatic quantum field theory - generalized Haag's theorem - is proven in SO(1,1) invariant quantum field theory, of which an important example is noncommutative quantum field theory. In SO(1,3) invariant theory new consequences of generalized Haag's theorem are obtained: it has been proved that equality of four-point Wightman functions in two theories leads to the equality of elastic scattering amplitudes and total cross-sections in these theories. 
M. Chaichian, M. Mnatsakanova, A. Tureanu and Yu. Vernov