Pseudodifferential operators on periodic graphs
  The main aim of the paper is Fredholm properties of a class of bounded linear operators acting on weighted Lebesgue spaces on an infinite metric graph $\Gamma$ which is periodic with respect to the action of the group ${\mathbb Z}^n$. The operators under consideration are distinguished by their local behavior: they act as (Fourier) pseudodifferential operators in the class $OPS^0$ on every open edge of the graph, and they can be represented as a matrix Mellin pseudodifferential operator on a neighborhood of every vertex of $\Gamma$. We apply these results to study the Fredholm property of a class of singular integral operators and of certain locally compact operators on graphs. 
Vladimir S. Rabinovich, Steffen Roch
math.FA