Fractional Laplacians and extension problems: the higher rank case
  The aim of this paper is two-fold: first, we look at the fractional Laplacian and the conformal fractional Laplacian from the general framework of representation theory on symmetric spaces and, second, we construct new boundary operators with good conformal properties that generalize the fractional Laplacian using an extension problem in which the boundary is of codimension two. 
Maria del Mar Gonzalez, Mariel Saez
math.AP math.DG