Previous |  Up |  Next

Article

Keywords:
generalized absolute convergence; Vilenkin-Fourier series; modulus of continuity; multiplicative system
Summary:
We consider the Vilenkin orthonormal system on a Vilenkin group $G$ and the Vilenkin-Fourier coefficients $\hat {f}(n)$, $n\in \mathbb {N}$, of functions $f\in L^p(G)$ for some $1<p\le 2$. We obtain certain sufficient conditions for the finiteness of the series $\sum _{n=1}^{\infty }a_n|\hat {f}(n)|^r$, where $\{a_n\}$ is a given sequence of positive real numbers satisfying a mild assumption and $0<r<2$. We also find analogous conditions for the double Vilenkin-Fourier series. These sufficient conditions are in terms of (either global or local) moduli of continuity of $f$ and give multiplicative analogue of some results due to Móricz (2010), Móricz and Veres (2011), Golubov and Volosivets (2012), and Volosivets and Kuznetsova (2020).
References:
[1] Fine, N. J.: On the Walsh functions. Trans. Am. Math. Soc. 65 (1949), 372-414. DOI 10.1090/S0002-9947-1949-0032833-2 | MR 0032833 | Zbl 0036.03604
[2] Folland, G. B.: A Course in Abstract Harmonic Analysis. Textbooks in Mathematics. CRC Press, Boca Raton (2016). DOI 10.1201/b19172 | MR 3444405 | Zbl 1342.43001
[3] Ghodadra, B. L.: On $\beta$-absolute convergence of Vilenkin-Fourier series with small gaps. Kragujevac J. Math. 40 (2016), 91-104. DOI 10.5937/KgJMath1601091G | MR 3509605 | Zbl 1474.42108
[4] Gogoladze, L., Meskhia, R.: On the absolute convergence of trigonometric Fourier series. Proc. A. Razmadze Math. Inst. 141 (2006), 29-40. MR 2259020 | Zbl 1113.42004
[5] Golubov, B., Efimov, A., Skvortsov, V.: Walsh Series and Transforms: Theory and Applications. Mathematics and Its Applications. Soviet Series 64. Kluwer, Dordrecht (1991). DOI 10.1007/978-94-011-3288-6 | MR 1155844 | Zbl 0785.42010
[6] Golubov, B. I., Volosivets, S. S.: Generalized absolute convergence of single and double Fourier series with respect to multiplicative systems. Anal. Math. 38 (2012), 105-122. DOI 10.1007/s10476-012-0202-8 | MR 2925159 | Zbl 1265.42005
[7] Hewitt, E., Ross, K. A.: Abstract Harmonic Analysis. Vol. I. Structure of Topological Groups. Integration Theory. Group Representations. Die Grundlehren der mathematischen Wissenschaften 115. Springer, Berlin (1963). DOI 10.1007/978-1-4419-8638-2 | MR 0156915 | Zbl 0115.10603
[8] Izumi, M., Izumi, S.: On absolute convergence of Fourier series. Ark. Mat. 7 (1967), 177-184. DOI 10.1007/BF02591034 | MR 0221195 | Zbl 0189.07102
[9] Móricz, F.: Absolute convergence of Walsh-Fourier series and related results. Anal. Math. 36 (2010), 275-286. DOI 10.1007/s10476-010-0402-z | MR 2738321 | Zbl 1240.42131
[10] Móricz, F., Veres, A.: Absolute convergence of double Walsh-Fourier series and related results. Acta Math. Hung. 131 (2011), 122-137. DOI 10.1007/s10474-010-0065-z | MR 2776656 | Zbl 1240.42132
[11] Onneweer, C. W.: Absolute convergence of Fourier series on certain groups. Duke Math. J. 39 (1972), 599-609. DOI 10.1215/S0012-7094-72-03965-8 | MR 0316976 | Zbl 0252.43016
[12] Quek, T. S., Yap, L. Y. H.: Absolute convergence of Vilenkin-Fourier series. J. Math. Anal. Appl. 74 (1980), 1-14. DOI 10.1016/0022-247X(80)90110-9 | MR 0568369 | Zbl 0434.43008
[13] Volosivets, S. S., Kuznetsova, M. A.: Generalized absolute convergence of single and double series in multiplicative systems. Math. Notes 107 (2020), 217-230. DOI 10.1134/S0001434620010216 | MR 4070005 | Zbl 1442.42016
[14] Walker, P. L.: Lipschitz classes on 0-dimensional groups. Proc. Camb. Philos. Soc. 63 (1967), 923-928. DOI 10.1017/S0305004100041906 | MR 0216246 | Zbl 0184.36301
[15] Younis, M. S.: On the absolute convergence of Vilenkin-Fourier series. J. Math. Anal. Appl. 163 (1992), 15-19. DOI 10.1016/0022-247X(92)90273-G | MR 1144701 | Zbl 0752.43007
Partner of
EuDML logo