“…The fractional Laplacian on the torus has been studied in [32] and several aspects of the harmonic analysis of the fractional Laplacian on lattices have been investigated in [8]. Other recent works on the fractional Laplacian and its different generalisations have been considered in [1,[12][13][14][15]17,20,23,30,31,37] and the references therein. In particular, the counterpart of the results proved here for compact Lie groups have been analysed on graded Lie groups in [4] in the case of hypoelliptic problems for Rockland operators.…”