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.Comment: Lattice 2000 (Topics in gauge theories); LaTeX with espcrc2, 4 page