Super-Ehlers in Any Dimension
  We classify the enhanced helicity symmetry of the Ehlers group to extended supergravity theories in any dimension. The vanishing character of the pseudo-Riemannian cosets occurring in this analysis is explained in terms of Poincar\'e duality. The latter resides in the nature of regularly embedded quotient subgroups which are non-compact rank preserving. 
Sergio Ferrara, Alessio Marrani, Mario Trigiante
hep-th