Correlation functions of chiral primary operators in perturbative {\cal   N}=4 SYM
  We discuss recent results on two-point functions of chiral primary operators in {\cal N}=4 SU(N) supersymmetric Yang-Mills theory. Our results give further support to the belief that such correlators are not renormalized to all orders in g and to all orders in N. 
S. Penati, A. Santambrogio and D. Zanon