Global Anomalies in M -theory

We first consider M -theory formulated on an open eleven-dimensional spin-manifold. There is then a potential anomaly under gauge transformations on the E8 bundle that is defined over the boundary and also under diffeomorphisms of the boundary. We then consider M -theory configurations that include a five-brane. In this case, diffeomorphisms of the eleven-manifold induce diffeomorphisms of the five-brane world-volume and gauge transformations on its normal bundle. These transformations are also potentially anomalous. In both of these cases, it has previously been shown that the perturbative anomalies, i.e. the anomalies under transformations that can be continuously connected to the identity, cancel. We extend this analysis to global anomalies, i.e. anomalies under transformations in other components of the group of gauge transformations and diffeomorphisms. These anomalies are given by certain topological invariants, that we explicitly construct. CERN-TH/97-277 October 1997