Almost everywhere convergence of $T$ means with respect to the Vilenkin system of integrable functions
Abstract
UDC 517.5
We prove and discuss some new weak-type (1,1) inequalities for the maximal operators of $T$ means with respect to the Vilenkin system generated by monotone coefficients. We also apply these results to prove that these $T$ means are almost everywhere convergent. As applications, we present both some well-known and new results.
References
G. N. Agaev, N. Ya. Vilenkin, G. M. Dzhafarli, A. I. Rubinstein, Multiplicative systems of functions and harmonic analysis on zero-dimensional groups} (in Russian), Baku, Elm (1981).
I. Blahota, On a norm inequality with respect to Vilenkin-like systems, Acta Math. Hungar., 89, № 1-2, 15–27 (2000).
I. Blahota, G. Tephnadze, Strong convergence theorem for Vilenkin–Fejér means, Publ. Math. Debrecen, 85, № 1-2, 181–196 (2014).
P. Billard, Sur la convergence presque partout des séries de Fourier–Walsh des fonctions de l'espace $L^2 [0,1]$, Studia Math., 28, 363–388 (1967).
I. Blahota, K. Nagy, L. E. Persson, G. Tephnadze, A sharp boundedness result concerning some maximal operators of partial sums with respect to Vilenkin systems, Georgian Math. J., 26, № 3, 351–360 (2019).
C. Demeter, Singular integrals along $N$ directions in $R^2,$} Proc. Amer. Math. Soc., 138, 4433–4442 (2010).
G. Gát, Cesàro means of integrable functions with respect to unbounded Vilenkin systems, J. Approx. Theory, 124, № 1, 25–43 (2003).
G. Gát, U. Goginava, Uniform and $L$-convergence of logarithmic means of Walsh–Fourier series, Acta Math. Sin., 22, № 2, 497–506 (2006).
G. Gát, U. Goginava, Almost everywhere convergence of a subsequence of the logarithmic means of quadratical partial sums of double Walsh–Fourier series, Publ. Math. Debrecen, 71, № 1-2, 173–184 (2007).
U. Goginava, K. Nagy, On the maximal operator of Walsh–Kaczmarz–Fejer means, Czechoslovak Math. J., 61, № 3, 673–686 (2011).
J. A. Gosselin, Almost everywhere convergence of Vilenkin–Fourier series, Trans. Amer. Math. Soc., 185, 345–370 (1973).
B. I. Golubov, A. V. Efimov, V. A. Skvortsov, Walsh series and transforms} (in Russian), Nauka, Moscow (1987); English translation: Mathematics and its Applications, 64, Kluwer Acad. Publ. Group, Dordrecht (1991).
D. Lukkassen, L. E. Persson, G. Tephnadze, G. Tutberidze, Some inequalities related to strong convergence of Riesz logarithmic means of Vilenkin–Fourier series, J. Inequal. and Appl. (2020); DOI: https, //doi.org/10.1186/s13660-020-02342-8.
F. Móricz, A. Siddiqi, Approximation by Nörlund means of Walsh–Fourier series (English summary), J. Approx. Theory, 70, № 3, 375–389 (1992).
K. Nagy, Approximation by Nörlund means of Walsh–Kaczmarz–Fourier series, Georgian Math. J., 18, № 1, 147–162 (2011).
K. Nagy, Approximation by Nörlund means of quadratical partial sums of double Walsh–Fourier series, Anal. Math., 36, № 4, 299–319 (2010).
K. Nagy, Approximation by Nörlund means of double Walsh–Fourier series for Lipschitz functions, Math. Inequal. and Appl., 15, № 2, 301–322 (2012).
K. Nagy, G. Tephnadze, Walsh–Marcinkiewicz means and Hardy spaces, Cent. Eur. J. Math., 12, № 8, 1214–1228 (2014).
K. Nagy, G. Tephnadze, Approximation by Walsh–Marcinkiewicz means on the Hardy space, Kyoto J. Math., 54, № 3, 641–652 (2014).
K. Nagy, G. Tephnadze, Strong convergence theorem for Walsh–Marcinkiewicz means, Math. Inequal. and Appl., 19, № 1, 185–195 (2016).
K. Nagy, G. Tephnadze, The Walsh–Kaczmarz–Marcinkiewicz means and Hardy spaces, Acta Math. Hungar., 149, № 2, 346–374 (2016).
J. Pál, P. Simon, On a generalization of the concept of derivative, Acta Math. Acad. Sci. Hungar., 29, № 1-2, 155–164 (1977).
L.-E. Persson, F. Schipp, G. Tephnadze, F. Weisz, An analogy of the Carleson–Hunt theorem with respect to Vilenkin systems, J. Fourier Anal. and Appl., 28, Article 48 (2022).
L. E. Persson, G. Tephnadze, P. Wall, Maximal operators of Vilenkin–Nörlund means, J. Fourier Anal. and Appl., 21, № 1, 76–94 (2015).
L. E. Persson, G. Tephnadze, P. Wall, On an approximation of 2-dimensional Walsh–Fourier series in the martingale Hardy spaces, Ann. Funct. Anal., 9, № 1, 137–150 (2018).
L. E. Persson, G. Tephnadze, P. Wall, Some new $(H_p,L_p)$ type inequalities of maximal operators of Vilenkin–Nörlund means with non-decreasing coefficients, J. Math. Inequal., 9, № 4, 1055–1069 (2015).
L. E. Persson, G. Tephnadze, P. Wall, On an approximation of 2-dimensional Walsh–Fourier series in the martingale Hardy spaces, Ann. Funct. Anal., 9, № 1, 137–150 (2018).
L. E. Persson, G. Tephnadze, G. Tutberidze, On the boundedness of subsequences of Vilenkin–Fejér means on the martingale Hardy spaces, Operators and Matrices, 14, № 1, 283–294 (2020).
L. E. Persson, G. Tephnadze, G. Tutberidze, P. Wall, Strong summability result of Vilenkin–Fejér means on bounded Vilenkin groups, Ukr. Math. J., 73, № 4, 544–555 (2021).
F. Schipp, F. Certain rearrangements of series in the Walsh system} (in Russian), Mat. Zametki, 18, № 2, 193–201 (1975).
F. Schipp, Pointwise convergence of expansions with respect to certain product systems, Anal. Math., 2, 65–76 (1976).
F. Schipp, Universal contractive projections and a.e. convergence, Probability Theory and Applications, Essays to the Memory of József Mogyoródi, Kluwer Acad. Publ., Dordrecht etc. (1992), p. 47–75.
F. Schipp, F. Weisz, Tree martingales and almost everywhere convergence of Vilenkin–Fourier series, Math. Pannon., 8, 17–36 (1997).
F. Schipp, W. R. Wade, P. Simon, J. Pál, Walsh series. An introduction to dyadic harmonic analysis, Adam Hilger, Ltd., Bristol (1990).
P. Sjölin, An inequality of Paley and convergence a.e. of Walsh–Fourier series, Ark. Mat., 8, 551–570 (1969).
P. Simon, Strong convergence theorem for Vilenkin–Fourier series, J. Math. Anal. and Appl., 245, 52–68 (2000).
P. Simon, Strong convergence of certain means with respect to the Walsh–Fourier series, Acta Math. Hungar., 49, № 3-4, 425–431 (1987).
G. Tephnadze, On the maximal operators of Vilenkin–Fejér means, Turkish J. Math., 37, № 2, 308–318 (2013).
G. Tephnadze, On the maximal operators of Vilenkin–Fejér means on Hardy spaces, Math. Inequal. and Appl., 16, № 2, 301–312 (2013).
G. Tephnadze, On the maximal operators of Walsh–Kaczmarz–Fejér means, Period. Math. Hungar., 67, № 1, 33–45 (2013).
G. Tephnadze, Approximation by Walsh–Kaczmarz–Fejér means on the Hardy space, Acta Math. Sci., 34, № 5, 1593–1602 (2014).
G. Tephnadze, On the maximal operators of Riesz logarithmic means of Vilenkin–Fourier series, Stud. Sci. Math. Hungar., 51, № 1, 105–120 (2014).
G. Tephnadze, On the partial sums of Walsh–Fourier series, Colloq. Math., 141, № 2, 227–242 (2015).
G. Tephnadze, On the partial sums of Vilenkin–Fourier series, J. Contemp. Math. Anal., 49, № 1, 23–32 (2014).
G. Tutberidze, Sharp $(H_p,L_p)$ type inequalities of maximal operators of means with respect to Vilenkin systems with monotone coefficients, Mediterr. J. Math. (to appear).
G. Tutberidze, Maximal operators of $T$ means with respect to the Vilenkin system, Nonlinear Stud., 27, № 4, 1–11 (2020).
N. Vilenkin, On a class of complete orthonormal systems, Amer. Math. Soc. Transl., 28, № 2, 1–35 (1963).
F. Weisz, Cesáro summability of one and two-dimensional Fourier series, Anal. Math. Stud., 5, 353–367 (1996).
F. Weisz, $Q$-summability of Fourier series, Acta Math. Hungar., 103, № 1-2, 139–175 (2004).
F. Weisz, Martingale Hardy spaces and their applications in Fourier-analysis, Lecture Notes in Math., vol. 1568, Springer, Berlin etc. (1994).
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