New Results on N=4 SuperYang-Mills Theory
  The N=4 SuperYang--Mills theory is covariantly determined by a U(1) \times SU(2) \subset SL(2,R) \times SU(2) internal symmetry and two scalar and one vector BRST topological symmetry operators. This determines an off-shell closed sector of N=4 SuperYang-Mills, with 6 generators, which is big enough to fully determine the theory, in a Lorentz covariant way. This reduced algebra derives from horizontality conditions in four dimensions. The horizontality conditions only depend on the geometry of the Yang-Mills fields. They also descend from a genuine horizontality condition in eight dimensions. In fact, the SL(2,R) symmetry is induced by a dimensional reduction from eight to seven dimensions, which establishes a ghost-antighost symmetry, while the SU(2) symmetry occurs by dimensional reduction from seven to four dimensions. When the four dimensional manifold is hyperKahler, one can perform a twist operation that defines the N=4 supersymmetry and its SL(2,H)\sim SU(4) R-symmetry in flat space. (For defining a TQFT on a more general four manifold, one can use the internal SU(2)-symmetry and redefine a Lorentz SO(4) invariance). These results extend in a covariant way the light cone property that the N=4 SuperYang-Mills theory is actually determined by only 8 independent generators, instead of the 16 generators that occur in the physical representation of the superPoincare algebra. The topological construction disentangles the off-shell closed sector of the (twisted) maximally supersymmetric theory from the (irrelevant) sector that closes only modulo equations of motion. It allows one to escape the question of auxiliary fields in N=4 SuperYang-Mills theory. 
Laurent Baulieu (LPTHE), Guillaume Bossard (LPTHE)