  The large radius limit in the AdS/CFT correspondence is expected to provide a
holographic derivation of flat-space scattering amplitudes. This suggests that
questions of locality in the bulk should be addressed in terms of properties of
the S-matrix and their translation into the conformal field theory. There are,
however, subtleties in this translation related to generic growth of amplitudes
near the boundary of anti de-Sitter space. Flat space amplitudes are recovered
after a delicate projection of CFT correlators onto normal-mode frequencies of
AdS. Once such amplitudes are obtained from the CFT, possible criteria for
approximate bulk locality include bounds on growth of amplitudes at high
energies and reproduction of semiclassical gravitational scattering at long
distances.
