Algebra of Calderón-Zygmund operators associated to para-accretive functions

By use of special wavelet bases associated to accretive or pseudo-accretive functions, it was proved that all Calderón-Zygmund operators satisfying certain conditions form an algebra. In this article, a similar result is proved for more general para-accretive functions. Since wavelet bases are not available for this general setting, the new idea used here is to apply the discrete Calderón-type reproducing formula associated to para-accretive functions developed in [14]. This new method can be applied to many other problems, where wavelet bases are not available.