NONPERTURBATIVE EFFECTS IN ADS(5)XS(5) STRING THEORY AND D=4 SUSY YANG-MILLS

We show that five-dimensional anti de-Sitter space remains a solution to low-energy type IIB supergravity when the leading higher-derivative corrections to the classical supergravity (which are non-perturbative in the string coupling) are included. Furthermore, at this order in t he low energy expansion of the IIB theory the graviton two-point and t hree-point functions in AdS(5) x S-5 are shown not to be renormalized and a precise expression is obtained for the four-graviton and related S-matrix elements. By invoking Maldacena's conjectured connection bet ween IIB superstring theory and supersymmetric Yang-Mills theory corre sponding statements are obtained concerning correlation functions of t he energy-momentum tensor and related operators in the large-N Yang-Mi lls theory. This leads to interesting non-perturbative statements and insights into the role of instantons in the gauge theory.