Abstract
We construct functions in the disc algebra whose Fourier series are pointwise universal on countable and dense sets and their sets of divergence contain Gδ and dense sets and have Hausdorff dimension zero. We also see that some classes of closed sets of measure zero do not accept uniformly universal Fourier series, although all such sets accept divergent Fourier series.
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References
F. Bayart and Y. Heurteaux, Multifractal analysis for the divergence of Fourier series: The extreme cases, J. Anal. Math. 124 (2014), 387–408.
G. Herzog and P. C. Kunstmann, Universally divergent Fourier series via Landau’s extremal functions, Comment. Math. Univ. Carolinae 56 (2015), 159–168.
Y. Katznelson, Introduction to Harmonic Analysis, 3rd edidtion, Cambridge Univ. Press, Cambridge, 2004.
J. P. Kahane, Baire’s category theorem and trigonometric series, J. Anal. Math. 80 (2000), 143–182.
E. Katsoprinakis, V. Nestoridis, and C. Papachristodoulos, Universality and Cesaro summability, Comp. Methods and Function Theory 12 (2012), 419–448.
T. W. Körner, Kahane’s Helson curve, J. Fourier Anal. Appl. 1 (1995), 325–346.
J. Müller, Continuous functions with universally divergent Fourier series on small subsets of the circle, C. R. Acad. Sci. Paris, Ser. I 348 (2010), 1155–1158.
V. Nestoridis, Universal Taylor series, Ann. Inst. Fourier 46, (1996), 1293–1306.
J. Oxtoby, Measure and Category, 2nd edition, Springer-Verlag Inc., New York, 1980.
A. Zygmund, Trigonometric Series, Vol. I, 3rd edition, Cambridge Univ. Press, Cambridge, 2002.
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Supported by the project 3083-FOURIERDIG which is implemented under the “Aristeia II” Action of the “Operational Programme Education and Lifelong Learning” and is co-founded by the European Social Fund (ESF) and National Resources.
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Papachristodoulos, C., Papadimitrakis, M. On universality and convergence of the Fourier series of functions in the disc algebra. JAMA 137, 57–71 (2019). https://doi.org/10.1007/s11854-018-0065-4
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DOI: https://doi.org/10.1007/s11854-018-0065-4