The maximal singular integral : estimates in terms of the singular integral

Abstract

This is an expository paper on the characterization of the even (or odd) smooth homogeneous convolution Calderón-Zygmund operators in R^n such that the maximal singular integral can be controlled in the L^2 norm by the singular integral. We focuss attention on special cases of the general statements to convey the main ideas of the proofs in a transparent way, as free as possible of the technical complications inherent to the general case. Particular attention is devoted to higher Riesz transforms. The exposition is based on two papers by J.Mateu, J.Orobitg, C.Pérez and J.Verdera published in 2010 and 2011.

This paper will appear in the Proceedings of the XXXI Conference in Harmonic Analysis, Rome, June 2011, to be published soon by Springer