Yang-Lee Edge Singularity on a Class of Treelike Lattices
  The density of zeros of the partition function of the Ising model on a class of treelike lattices is studied. An exact closed-form expression for the pertinent critical exponents is derived by using a couple of recursion relations which have a singular behavior near the Yang-Lee edge. 
Milan Knezevic and Suncica Elezovic-Hadzic