Nilpotent invariants in N=4 SYM

It is shown that there are no nilpotent invariants in N=4 analytic superspace for n≤4 points. It is argued that there is (at least) one such invariant for n=5 points which is not invariant under U(1)Y. The consequences of these results are that the n=2 and 3 point correlation functions of the N=4 gauge-invariant operators which correspond to KK multiplets in AdS supergravity are given exactly by their tree level expressions, the 4 point correlation functions of such operators are invariant under U(1)Y and correlation functions with n≥4 points have non-trivial dependence on the Yang-Mills coupling constant.