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Zapiski Nauchnykh Seminarov POMI, 2011, Volume 389, Pages 21–33
(Mi znsl4116)
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Extension of a theorem by Hardy and Littlewood
S. V. Bykov I. G. Petrovsky Bryansk State University, Bryansk
Abstract:
We give the following extension of a theorem by Hardy and Littlewood. Suppose $f$ is a holomorphic function in the unit disk and
$$
M_p(r,f)=\Bigl(\frac1{2\pi}\int_{-\pi}^\pi|f(re^{i\theta})|^pd\theta\Bigr)^{\frac1p}=O(\varphi(r)),\quad r\to1-0,
$$
where $\varphi$ is a monotone increasing function on $(0,1)$ and
$$
\alpha_\varphi=\lim_{r\to1-0}\frac{\varphi'(r)(1-r)}{\varphi(r)}.
$$
1) If $0\leq\alpha_\varphi<+\infty$, then $M_p(r,f')=O(\frac{\varphi(r)}{1-r})$, $r\to1-0$;
2) If $\alpha_\varphi=+\infty$, then $M_p(r,f')=O(\varphi'(r))$, $r\to1-0$.
Key words and phrases:
holomorphic function, unit disk, Hardy–Littlewood theorem.
Received: 24.06.2011
Citation:
S. V. Bykov, “Extension of a theorem by Hardy and Littlewood”, Investigations on linear operators and function theory. Part 39, Zap. Nauchn. Sem. POMI, 389, POMI, St. Petersburg, 2011, 21–33; J. Math. Sci. (N. Y.), 182:5 (2012), 595–602
Linking options:
https://www.mathnet.ru/eng/znsl4116 https://www.mathnet.ru/eng/znsl/v389/p21
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Abstract page: | 195 | Full-text PDF : | 79 | References: | 32 |
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