  We study the structure of the four-point correlation function of the
lowest-dimension 1/2 BPS operators (stress-tensor multiplets) in the (2,0)
six-dimensional theory. We first discuss the superconformal Ward identities and
the group-theoretical restrictions on the corresponding OPE. We show that the
general solution of the Ward identities is expressed in terms of a single
function of the two conformal cross-ratios ("prepotential"). Using the
maximally extended gauged seven-dimensional supergravity, we then compute the
four-point amplitude in the supergravity approximation and identify the
corresponding prepotential. We analyze the leading terms in the OPE by
performing a conformal partial wave expansion and show that they are in
agreement with the non-renormalization theorems following from representation
theory. The investigation of the (2,0) theory is carried out in close parallel
with the familiar four-dimensional N=4 super-Yang-Mills theory.
