Particles on AdS_{4/7} and Primary Operators on M_{2/5} Brane   Worldvolumes
  1 identify a correspondence between the various spherical harmonic modes of massless 11 dimensional fields propagating on the $AdS_{4/7}$ in an $AdS_{4/7} \times S^{7\4}$ compactification of M theory, and the corresponding operators, primary under the conformal group, on the world volume of $M_2,M_5$ branes. This is achieved by matching representations of the superconformal algebra on the two sides of the correspondence. 
Shiraz Minwalla