N=31, D=11
arXiv:hep-th/0610331 · doi:10.1088/1126-6708/2007/02/043
Abstract
We show that eleven-dimensional supergravity backgrounds with thirty one supersymmetries, N=31, admit an additional Killing spinor and so they are locally isometric to maximally supersymmetric ones. This rules out the existence of simply connected eleven-dimensional supergravity preons. We also show that N=15 solutions of type I supergravities are locally isometric to Minkowski spacetime.
17 pages