RG flow in an exactly solvable model with fluctuating geometry
  A recently proposed renormalization group technique, based on the hierarchical structures present in theories with fluctuating geometry, is implemented in the model of branched polymers. The renormalization group equations can be solved analytically, and the flow in coupling constant space can be determined. 
Jan Ambjorn, Piotr Bialas and Jerzy Jurkiewicz