Superconformal Invariants or How to Relate Four-point AdS Amplitudes
  Using the form of N=2 superconformal invariants we derive the explicit relation between the bottom and top components of the correlator of four stress-tensor multiplets in N=4 Super Yang-Mills. The result is given in terms of an eighth order differential operator acting on the function of two variables which characterises these correlators. It allows us to show a non-trivial consistency relation between the known results for the corresponding supergravity amplitudes on AdS5. 
J.M.Drummond, L.Gallot, E.Sokatchev