SPIN AND GAUGE SYSTEMS ON SPHERICAL LATTICES

We present results for 2D and 4D systems on lattices with topology hom otopic to the surface of a (hyper) sphere S-2 or S-4. Finite size scal ing is studied in situations with phase transitions of first and secon d order type. The Ising and Potts models exhibit the expected behaviou r; for the 4D pure gauge U(1) theory we find consistent scaling indica tive of a second order phase transition with critical exponent nu simi lar or equal to 0.36(1).