A Mourre estimate for a Schroedinger operator on a binary tree
  Let G be a binary tree with vertices V and let H be a Schroedinger operator acting on l^{2}(V). A decomposition of the space l^{2}(V) into invariant subspaces is exhibited yielding a conjugate operator A, for use in the Mourre estimate. We show that for potentials q satisfying a first order difference decay condition, a Mourre estimate for H holds. 
C. Allard, R. Froese