Orbifolds of AdS(3) and fixpoints of the CFT
  The 3-d BTZ black hole represents an orbifold of $AdS_3$ gravity. The UV as well as the IR region of the CFT is governed by a gauged SL(2, R) WZW model. In the UV it corresponds to a light-cone gauging (Liouville model) whereas in the IR it is a space-like gauging (2-d black hole). 
Klaus Behrndt