Discrete reflection groups and induced representations of Poincare group   on the lattice
  We continue the program, presented in previous Symposia, of discretizing physical models. In particular we calculate the integral Lorentz transformations with the help of discrete reflection groups, and use them for the covariance of Klein-Gordon and Dirac wave equation on the lattice. Finally we define the unitary representation of Poincar group on discrete momentum and configuration space, induced by integral representations of its closed subgroup. 
M. Lorente