Quasi-local formulation of the mirror TBA
  We present a method of removing all infinite sums from the various forms of the mirror TBA equations and the energy formula of the AdS/CFT spectral problem. This new formulation of the TBA system is quasi-local because Y-functions that are connected by the TBA equations are at most next to nearest neighbors with respect to the Y-system diagram of AdS/CFT. 
Janos Balog and Arpad Hegedus
hep-th