Theories with global gauge anomalies on the lattice
  A global anomaly in a chiral gauge theory manifests itself in different ways in the continuum and on the lattice. In the continuum case, functional integration of the fermion determinant over the whole space of gauge fields yields zero. In the case of the lattice, it is not even possible to define a fermion measure over the whole space of gauge configurations. However, this is not necessary, and as in the continuum, a reduced functional integral is sufficient for the existence of the theory. 
P. Mitra