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Analytic functions with smooth absolute value of boundary data
F. A. Shamoyan Bryansk State University
named after Academician Ivan Georgiyevich Petrovsky,
Bezhitsckaya str. 14,
241036, Bryansk, Russia
Abstract:
Let $f$ be an analytic function in the unit circle $D$ continuous up to its boundary $\Gamma$, $f(z) \neq 0$, $z \in D$. Assume that on $\Gamma$, the function $|f|$ has a modulus of continuity $\omega(|f|,\delta)$. In the paper we establish the estimate $\omega(f,\delta) \leq A\omega(|f|, \sqrt{\delta})$, where $A$ is a some non-negative number, and we prove that this estimate is sharp. Moreover, in the paper we establish a multi-dimensional analogue of the mentioned result.
In the proof of the main theorem, an essential role is played by a theorem of Hardy–Littlewood type on Hölder classes of the functions analytic in the unit circle.
Keywords:
analytic function, modulus of continuity, factorization, outer function.
Received: 10.05.2017
Citation:
F. A. Shamoyan, “Analytic functions with smooth absolute value of boundary data”, Ufa Math. J., 9:3 (2017), 148–157
Linking options:
https://www.mathnet.ru/eng/ufa396https://doi.org/10.13108/2017-9-3-148 https://www.mathnet.ru/eng/ufa/v9/i3/p148
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Abstract page: | 252 | Russian version PDF: | 95 | English version PDF: | 16 | References: | 46 |
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