On the range of the simple random walk bridge on groups
  Let G be a vertex transitive graph. A study of the range of simple random walk on G and of its bridge is proposed. While it is expected that on a graph of polynomial growth the sizes of the range of the unrestricted random walk and of its bridge are the same in first order, this is not the case on some larger graphs such as regular trees. Of particular interest is the case when G is the Cayley graph of a group. In this case we even study the range of a general symmetric (not necessarily simple) random walk on G. We hope that the few examples for which we calculate the first order behavior of the range here will help to discover some relation between the group structure and the behavior of the range. Further problems regarding bridges are presented. 
Itai Benjamini, Roey Izkovsky, Harry Kesten