Estimates of Partial Derivatives for Harmonic Functions on the Unit Disc

IF 0.6 4区 数学 Q3 MATHEMATICS Computational Methods and Function Theory Pub Date : 2023-12-22 DOI:10.1007/s40315-023-00514-3
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引用次数: 0

Abstract

Let \(f = P[F]\) denote the Poisson integral of F in the unit disc \({{\mathbb {D}}}\) with F absolutely continuous on the unit circle \({{\mathbb {T}}}\) and \(\dot{F}\in L^p({{\mathbb {T}}})\) , where \(\dot{F}(e^{it}) = \frac{d}{dt} F(e^{it})\) . We show that for \(p\in (1,\infty )\) , the partial derivatives \(f_z\) and \(\overline{f_{\bar{z}}}\) belong to the holomorphic Hardy space \(H^p({{\mathbb {D}}})\) . In addition, for \(p=1\) or \(p=\infty \) , \(f_z\) and \(\overline{f_{\bar{z}}}\in H^p({{\mathbb {D}}})\) if and only if \(H(\dot{F})\in L^p({{\mathbb {T}}})\) , the Hilbert transform of \(\dot{F}\) and in that case, we have \(2izf_z=P[\dot{F}+iH(\dot{F})]\) . Our main tools are integral representations of \(f_z\) and \(f_{\overline{z}}\) in terms of \(\dot{F}\) and M. Riesz’s theorem on conjugate functions. This simplifies and extends the recent results of Chen et al. [1] (J. Geom. Anal., 2021) and Zhu [17] (J. Geom. Anal., 2021).

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单位圆盘上谐函数偏导数的估计值
Abstract Let \(f = P[F]\) denote the Poisson integral of F in the unit disc \({{\mathbb {D}}}) with F absolutely continuous on the unit circle \({{\mathbb {T}}}\) and\(\dot{F}\in L^p({{\mathbb {T}}})\.其中 \(\dot{F}(e^{it}) = \frac{d}{dt}F(e^{it})\) 。我们证明对于 \(p\in (1,\infty )\)的偏导数 \(f_z\) 和 \(\overline{f_{bar\{z}}) 属于全形哈代空间 \(H^p({{mathbb {D}})\) 。此外,对于(p=1)或(p=infty),当且仅当(H(dot{F})\in L^p({{\mathbb {T}}}))时,(f_z)和(overline{f_{bar{z}}}\in H^p({{\mathbb {D}}}))。在这种情况下,我们就有\(2izf_z=P[\dot{F}+iH(\dot{F})]\) 。我们的主要工具是 \(f_z\) 和 \(f_{\overline{z}}\) 在 \(\dot{F}\) 和 M. Riesz 的共轭函数定理方面的积分表示。这简化并扩展了 Chen 等人 [1] (J. Geom. Anal., 2021) 和 Zhu [17] (J. Geom. Anal., 2021) 的最新成果。
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来源期刊
Computational Methods and Function Theory
Computational Methods and Function Theory MATHEMATICS, APPLIED-MATHEMATICS
CiteScore
3.20
自引率
0.00%
发文量
44
审稿时长
>12 weeks
期刊介绍: CMFT is an international mathematics journal which publishes carefully selected original research papers in complex analysis (in a broad sense), and on applications or computational methods related to complex analysis. Survey articles of high standard and current interest can be considered for publication as well.
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