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Related papers: Landau type theorem for $\alpha$-harmonic mappings

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The aim of this paper is to obtain the Schwarz-Pick type inequality for $\alpha$-harmonic functions $f$ in the unit disk and get estimates on the coefficients of $f$. As an application, a Landau type theorem of $\alpha$-harmonic functions…

Complex Variables · Mathematics 2017-05-30 Peijin Li , Xiantao Wang , Qianhong Xiao

Let $f(z)=h(z)+\overline{g(z)}$ be a harmonic mapping of the unit disk $U$. In this paper, the sharp coefficient estimates for bounded planar harmonic mappings are established, the sharp coefficient estimates for normalized planar harmonic…

Complex Variables · Mathematics 2015-11-17 Ming-Sheng Liu , Zhi-Wen Liu , Yu-Can Zhu

In this paper, we first investigate coefficient estimates for bounded polyharmonic mappings in the unit disk $\mathbb{D}$. Then, we obtain two versions of Landau's theorem for polyharmonics mapping $F$, and for the mappings of the type…

Complex Variables · Mathematics 2014-06-18 Jiaolong Chen , Antti Rasila , Xiantao Wang

The aim of this paper is twofold. First, we obtain a Schwarz-Pick type lemma for the $\alpha$-harmonic mapping $u=P_{\alpha}[\phi]$, where $\phi\in L^{p}(\mathbb{S}^{n-1},\mathbb{R} )$ and $p\in[1,\infty]$. We get an explicit form of the…

Analysis of PDEs · Mathematics 2025-09-09 Vibhuti Arora , Jiaolong Chen , Shankey Kumar , Qianyun Li

In this paper, we investigate the properties of locally univalent and multivalent planar harmonic mappings. First, we discuss the coefficient estimates and Landau's Theorem for some classes of locally univalent harmonic mappings, and then…

Complex Variables · Mathematics 2014-06-18 Shaolin Chen , Saminathan Ponnusamy , Antti Rasila

In this article, we obtain certain estimates for the Taylor coefficients of $(K,K')$-elliptic harmonic mappings and using these estimates, we prove a Landau-type theorem for these mappings. We also derive Bloch constant for the class of…

Complex Variables · Mathematics 2024-04-09 Bappaditya Bhowmik , Sambhunath Sen

In this paper, we establish an improved coefficient bounds for quasiregular and elliptic harmonic mappings and using these bounds we establish Landau-Bloch type theorem for $(K,K')$-elliptic and K-quasiregular harmonic mappings in plane.…

Complex Variables · Mathematics 2026-04-14 Vasudevarao Allu , Rohit Kumar

In the present article, we investigate the univalence property of polyanalytic functions and $\log$-$\alpha$-analytic functions. First, by using a new idea, we prove an improved lemma and the coefficient estimates for bounded polyanalytic…

Complex Variables · Mathematics 2025-10-06 P. Li , M. -S. Liu , S. Ponnusamy , H. Zhao

In this study, we establish certain Landau-type theorems for functions with logharmonic Laplacian of the form $F(z)=|z|^2L(z)+K(z)$, $|z|<1$, where $L$ is logharmonic and $K$ is harmonic, with $L$ and $K$ having bounded length distortion in…

Complex Variables · Mathematics 2025-02-13 Sudip Kumar Guin , Rajib Mandal

In this paper, we establish three new versions of Landau-type theorems for bounded bi-analytic functions of the form $F(z)=\bar{z}G(z)+H(z)$, where $G$ and $H$ are analytic in the unit disk $|z|<1$ with $G(0)=H(0)=0$ and $H'(0)=1$. In…

Complex Variables · Mathematics 2023-02-16 Ming-Sheng Liu , Saminathan Ponnusamy

Let $\mathcal{H}$ be the class of all complex-valued harmonic mappings $f=h+\overline{g}$ defined on the unit disc $\mathbb{D}=\{z\in\mathbb{C}:|z|<1\}$ with the normalization $h(0)=0=h'(0)-1$, here $h$ and $g$ are analytic functions in…

Complex Variables · Mathematics 2026-04-01 Molla Basir Ahamed , Rajesh Hossain

In this paper, we first establish Landau-Bloch-type theorems for poly $(K,K')$-elliptic harmonic mappings, which are sharp in some given cases. Thereafter, we provide several coefficient bounds for $(K,K')$-elliptic and $K$-quasiregular…

Complex Variables · Mathematics 2026-03-20 Rajib Mandal , Sudip Kumar Guin

In this paper, we establish two new versions of Landau-type theorems for pluriharmonic mappings with a bounded distortion. Then using these results, we derive three Bloch-type theorems of pluriharmonic mappings, which improve the…

Complex Variables · Mathematics 2022-02-17 Ming-Sheng Liu , Saminathan Ponnusamy

Let $\alpha>-1$ and assume that $f$ is $\alpha-$harmonic mapping defined in the unit disk that belongs to the Hardy class $h^p$ with $p\ge 1$. We obtain some sharp estimates of the type $|f(z)|\le g(|r|) \|f^\ast\|_p$ and $|Df(z)|\le…

Complex Variables · Mathematics 2024-02-27 David Kalaj

We call a kind of mappings induced by a kind of weighted Laplace operator as complex valued kernel $\alpha$-harmonic mappings. In this article, for this class of mappings, the Heinz type lemma is established, and the best Heinz type…

Complex Variables · Mathematics 2024-01-22 Boyong Long

In this paper, we first define two classes of holomorphic mappings defined on the unit ball $B^n$ of n-dimensional complex space $\mathbb{C}^n$ and obtain the lower estimates for Bloch's constant for these classes. Also, we derive the…

Complex Variables · Mathematics 2026-04-14 Vasudeva Rao Allu , Rohit Kumar

We consider the class univalent log-harmonic mappings on the unit disk. Firstly, we obtain necessary and sufficient conditions for a complex-valued continuous function to be starlike or convex in the unit disk. Then we present a general…

Complex Variables · Mathematics 2019-05-28 ZhiHong Liu , Saminathan Ponnusamy

In this paper, we continue our investigation of polyharmonic mappings in the complex plane. First, we establish two Landau type theorems. We also show a three circles type theorem and an area version of the Schwarz lemma. Finally, we study…

Complex Variables · Mathematics 2014-03-31 Jiaolong Chen , Antti Rasila , Xiantao Wang

In this paper, we establish some Schwarz type lemmas for mappings $\Phi$ satisfying the inhomogeneous biharmonic Dirichlet problem $ \Delta (\Delta(\Phi)) = g$ in $\mathbb{D}$, $\Phi=f$ on $\mathbb{T}$ and $\partial_n \Phi=h$ on…

Complex Variables · Mathematics 2020-03-26 Adel Khalfallah , Fathi Haggui , Mohamed Mhamdi

The classical Fatou theorem identifies bounded harmonic functions on the unit disk with bounded measurable functions on the boundary circle. We extend this theorem to bounded harmonic maps.

Differential Geometry · Mathematics 2023-08-29 Yves Benoist , Dominique Hulin
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