Discrete anomalies in supergravity and consistency of string backgrounds
  We examine SL(2, Z) anomalies in ten and eight-dimensional supergravities, the induced local counterterms and their realization in string theory. Composite connections play an important role in the cancellation mechanism. At the same time their global properties lead to novel non-trivial consistency constraints on compactifications. 
Ruben Minasian, Soumya Sasmal, Raffaele Savelli
hep-th