Left coset invariance and relativisitc invariance

The concept of left coset invariance is introduced as a means for investigating Poincare invariance in dynamical models. In many cases of interest it is possible to construct model Hamiltonians, mass operators, or scattering matrix elements without having an explicit dynamical representation of the Poincare group on the model Hilbert space. Left coset invariance of the S-matrix provides a means, using only kinematic transformations, to establish the existence of an underlying representation of the Poincare group. (author)