A Solvable 2D Quantum Gravity Model with $\GAMMA >0$
  We consider a model of discretized 2d gravity interacting with Ising spins where phase boundaries are restricted to have minimal length and show analytically that the critical exponent $\gamma= 1/3$ at the spin transition point. The model captures the numerically observed behavior of standard multiple Ising spins coupled to 2d gravity. 
J. Ambjorn, B. Durhuus and T. Jonsson