D=11 Supergravity Revisited
  I discuss two novel results in D=11 Supergravity. The first establishes, in two complementary ways, a no-go theorem that, in contrast to all D<11, a cosmological extension of the theory does not exist. The second deals with the structure of (on-shell) four-point invariants. These are important both for establishing existence of the lowest (2-loop) order candidate counter-terms in the theory proper, as well as for comparison with the form of eventual "zero-slope" QFT limit of M-theory. 
S. Deser (Brandeis University)