Perturbative terms of Kac-Moody-Eisenstein series
  Supersymmetric theories of gravity can exhibit surprising hidden symmetries when considered on manifolds that include a torus. When the torus is of large dimension these symmetries can become infinite-dimensional and of Kac-Moody type. When taking quantum effects into account the symmetries become discrete and invariant functions under these symmetries should play an important role in quantum gravity. The new results here concern surprising simplifications in the constant terms of very particular Eisenstein series on the these Kac-Moody groups. These are exactly the cases that are expected to arise in string theory. 
Philipp Fleig and Axel Kleinschmidt
hep-th