Pomeron Loops in High Energy QCD
  We discuss the QCD evolution equations governing the high energy behavior of scattering amplitudes at the leading logarithmic level. This hierarchy of equations accommodates normal BFKL dynamics, Pomeron mergings and Pomeron splittings. Pomeron loops are built in the course of evolution and the scattering amplitudes satisfy the unitarity bound. 
D.N. Triantafyllopoulos