In the Schwinger model with iso-spin on the torus the regularized effe
ctive action, the fermion propagator in a background field, and the co
rrelation functions of the fermion bilinears are calculated. These cal
culations illustrate in particular the dynamics of the U(L)(2) x U(R)(
2) symmetry breaking by an U(A)(1) axial anomaly, and the role of the
topological zero modes in this scheme.