On the relations between correlation functions in SYM/pp-wave correspondence

In this note we establish the explicit relation between correlation functions in ${\cal N} = 4$ SUSY Yang--Mills theory on $S^3\times R$ in a double scaling limit and scattering amplitudes of the String Theory on the pp-wave background. The relation is found for two-- and three--point correlation functions in these theories. As a by product we formulate a dictionary for the correspondence between these theories: in particular, we find some unknown relations between the parameters in these theories. Furthermore, we argue that the String Theory on the pp--wave background is related to four--dimensional SUSY Yang--Mills theory rather than to the reduced matrix quantum mechanics. We identify string theory excitations which are related to the Kaluza--Klein excitation of the Yang--Mills theory on $S^3$.