SYMMETRIC M-THEORY BACKGROUNDS

Abstract. We classify symmetric backgrounds of eleven-dimensional supergravity up to local isometry. In otherwords, we classify triples (M,g,F), where (M,g) is an eleven-dimensional lorentzian locally symmetric space and F is an invariant 4-form, satisfying the equations of motion of eleven-dimensional supergravity. The possible (M,g) are given either by (not necessarily nondegenerate) Cahen–Wallach spaces or by products AdSd×M11−d for 2 6 d 6 7 andM11−d a not necessarily irreducible riemannian symmetric space. In most cases we determine the corresponding F-moduli spaces. Content