On the world-volume of an M -theory five-brane propagates a two-form with selfdual field strength. As this field is non-Lagrangian, there is no obvious framework for determining its partition function. An analogous problem exists in Type IIB superstring theory for the self-dual five-form. The resolution of these problems and definition of the partition function is explained. A more complete analysis of perturbative anomaly cancellation for M -theory five-branes is also presented, uncovering… CONTINUE READING