Open Access Research

The maximal Hilbert transform along nonconvex curves

Honghai Liu

Author Affiliations

School of Mathematics and Information Science, Henan Polytechnic University, Jiaozuo, Henan, 454003, P.R. China

Journal of Inequalities and Applications 2012, 2012:191 doi:10.1186/1029-242X-2012-191

Published: 31 August 2012

Abstract

The Hilbert transform along curves is defined by the principal value integral. The pointwise existence of the principal value Hilbert transform can be educed from the appropriate estimates for the corresponding maximal Hilbert transform. By using the estimates of Fourier transforms and Littlewood-Paley theory, we obtain <a onClick="popup('http://www.journalofinequalitiesandapplications.com/content/2012/1/191/mathml/M1','MathML',630,470);return false;" target="_blank" href="http://www.journalofinequalitiesandapplications.com/content/2012/1/191/mathml/M1">View MathML</a>-boundedness for the maximal Hilbert transform associated to curves <a onClick="popup('http://www.journalofinequalitiesandapplications.com/content/2012/1/191/mathml/M2','MathML',630,470);return false;" target="_blank" href="http://www.journalofinequalitiesandapplications.com/content/2012/1/191/mathml/M2">View MathML</a>, where <a onClick="popup('http://www.journalofinequalitiesandapplications.com/content/2012/1/191/mathml/M3','MathML',630,470);return false;" target="_blank" href="http://www.journalofinequalitiesandapplications.com/content/2012/1/191/mathml/M3">View MathML</a>, P is a real polynomial and γ is convex on <a onClick="popup('http://www.journalofinequalitiesandapplications.com/content/2012/1/191/mathml/M4','MathML',630,470);return false;" target="_blank" href="http://www.journalofinequalitiesandapplications.com/content/2012/1/191/mathml/M4">View MathML</a>. Then, we can conclude that the Hilbert transform along curves <a onClick="popup('http://www.journalofinequalitiesandapplications.com/content/2012/1/191/mathml/M2','MathML',630,470);return false;" target="_blank" href="http://www.journalofinequalitiesandapplications.com/content/2012/1/191/mathml/M2">View MathML</a> exists in pointwise sense.

MSC: 42B20, 42B25.

Keywords:
the maximal Hilbert transform; maximal functions; nonconvex curves; Littlewood-Paley theory