Natural Science, Mathematics, 2025
ON THE DIVERGENCE OF WALSH AND HAAR SERIES BY SECTORIAL AND TRIANGULAR REGIONS
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Submitted: 2025-02-12; Published: 2025-02-12
© 2025 by author(s) and The Gufo Inc.
This work is licensed under Creative Commons Attribution–NonCommercial International License
(CC BY-NC 4.0).
Abstract
Almost everywhere (a.e.) divergence problems of the triangular and sectorial partial sums of the double Fourier series in Walsh and Haar orthonormal systems are studied. In particular, is constructed an example of bounded function on the unit square, which double Walsh–Fourier series diverges a.e. by an increasing sequence of triangular regions.