In this paper we study the AdS/CFT correspondence in the operator formalism
without assuming the GKPW relation. We explicitly show that the low energy
spectrum of the large N limit of CFT, which is realized by a strong coupling
gauge theory, is identical to the spectrum of the free gravitational theory in
the global AdS spacetime under some assumptions which are expected to be valid.
Thus, two theories are equivalent for the low energy region under the
assumptions. Using this equivalence, the bulk local field is constructed and
the GKPW relation is derived.Comment: 26 pages, references adde