  We study the radial quantization of the 3d O(N) vector model. We calculate
the higher spin charges whose commutation relations give the higher spin
algebra. The Fock states of higher spin gravity in AdS_{4} are realized as the
states in the 3d CFT. The inner products between these states encode dynamical
information. The construction of bulk operators from CFT is discussed as well.
This serves as the simplest explicit demonstration of the CFT definition for
the quantum gravity.
