The limit case of the Cesàro-α convergence of the ergodic averages and the ergodic Hilbert transform

Abstract

Recently, Sarrión and the authors gave a sufficient condition on invertible Lamperti operators on L^p which guarantees the convergence in the Cesàro-α sense of the ergodic averages and the ergodic Hilbert transform for all f ∈ L^p with p > 1/(1 + α) and −1 < α ≤ 0. The result does not hold for the space L^{1/(1 + α)}. In this paper we give a positive result for the smaller Lorentz space L_{1/(1 + α),1}.