Bi-local Model of AdS/CFT and Higher Spin Gravity
  We shortly review the bi-local, collective dipole mechanism to a construction of Higher Spin AdS Gravity from the O(N) vector field theory. We also make some comments regarding an exact nonlinear comparison and in this regard we present a bi-local (symmetric) gauge description of Vasiliev's theory. 
Antal Jevicki, Kewang Jin, Qibin Ye
hep-th