Instantons in supersymmetric Yang-Mills and d-instantons in IIB superstring theory

The one-instanton contributions to various correlation functions of superconformal currents in four-dimensional N = 4 supersymmetric SU(2) Yang-Mills theory are evaluated to the lowest order in perturbation theory. Expressions of the same form are obtained form the leading effects of a single D-instanton extracted from the IIB superstring effective action around the AdS(5) X S-5 background. This is in line with the suggested AdS/Yang-Mills correspondence. The relation between Yang-Mills instantons and D-instantons is further confirmed by ther explicit form of the classical D-instanton solution in the AdS(5) X S-5 background and its associated supermultiplet of zero modes. Speculations are made concerning instanton effects in the large-N-c limit of the SU(N-c) Yang-Mills theory