  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.
