Abstract:
It is proved that any continuous function $\varphi$ on the unit circle such that the sequence $\{e^{in\varphi}\}_{n\in\mathbb{Z}}$ has small Wiener norm $\|e^{in\varphi}\| = o(\log^{1/22}|n|(\log \log |n|)^{-3/11})$, $|n| \to \infty$, is linear. Moreover, lower bounds for the Wiener norms of the characteristic functions of subsets of $\mathbb{Z}_p$ in the case of prime $p$ are obtained.
Keywords:
Wiener norm, Beurling-Helson theorem, dissociated sets.
The first author acknowledges the support of RFBR grant no. 14-01-00332 and of the program "Leading Scientific Schools," grant no. 3082.2014.1. The second author acknowledges the support of RFBR grant no. 12-01-33080-mol_a_ved.
Citation:
S. V. Konyagin, I. D. Shkredov, “A quantitative version of the Beurling-Helson theorem”, Funktsional. Anal. i Prilozhen., 49:2 (2015), 39–53; Funct. Anal. Appl., 49:2 (2015), 110–121
\Bibitem{KonShk15}
\by S.~V.~Konyagin, I.~D.~Shkredov
\paper A quantitative version of the Beurling-Helson theorem
\jour Funktsional. Anal. i Prilozhen.
\yr 2015
\vol 49
\issue 2
\pages 39--53
\mathnet{http://mi.mathnet.ru/faa3185}
\crossref{https://doi.org/10.4213/faa3185}
\mathscinet{http://mathscinet.ams.org/mathscinet-getitem?mr=3374902}
\zmath{https://zbmath.org/?q=an:06486272}
\elib{https://elibrary.ru/item.asp?id=24849952}
\transl
\jour Funct. Anal. Appl.
\yr 2015
\vol 49
\issue 2
\pages 110--121
\crossref{https://doi.org/10.1007/s10688-015-0093-0}
\isi{https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=Publons&SrcAuth=Publons_CEL&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=000356443000005}
\elib{https://elibrary.ru/item.asp?id=23988504}
\scopus{https://www.scopus.com/record/display.url?origin=inward&eid=2-s2.0-84935847152}
Linking options:
https://www.mathnet.ru/eng/faa3185
https://doi.org/10.4213/faa3185
https://www.mathnet.ru/eng/faa/v49/i2/p39
This publication is cited in the following 7 articles:
Noga Alon, Matija Bucić, Lisa Sauermann, Dmitrii Zakharov, Or Zamir, “Essentially tight bounds for rainbow cycles in proper edge‐colourings”, Proceedings of London Math Soc, 130:4 (2025)
I.D. Shkredov, “Additive dimension and the growth of sets”, Discrete Mathematics, 347:9 (2024), 114077
M. R. Gabdullin, “Lower Bounds for the Wiener Norm in $\mathbb Z_p^d$”, Math. Notes, 107:4 (2020), 574–588
T. Sanders, “Bounds in cohen's idempotent theorem”, J. Fourier Anal. Appl., 26:2 (2020), 25
V. Lebedev, A. Olevskii, “Homeomorphic changes of variable and Fourier multipliers”, J. Math. Anal. Appl., 481:2 (2020), 123502
I. D. Shkredov, Trigonometric Sums and Their Applications, 2020, 261
V. Lebedev, “Quantitative aspects of the Beurling-Helson theorem: phase functions of a special form”, Studia Math., 247:3 (2019), 273–283