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Related papers: On harmonic functions and the Schwarz lemma

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Suppose $w$ is a sense-preserving harmonic mapping of the unit disk $\mathbb{D}$ such that $w(\mathbb{D})\subseteq\mathbb{D}$ and $w$ has a zero of order $p\geq1$ at $z=0$. In this paper, we first improve the Schwarz lemma for $w$, and…

Complex Variables · Mathematics 2020-07-28 Xiao-Jin Bai , Jie Huang , Jian-Feng Zhu

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

We establish some inequalities of Schwarz-Pick type for harmonic and hyperbolic harmonic functions on the unit ball of and we disprove a recent conjecture of Liu [Schwarz-Pick Lemma for Harmonic Functions, International Mathematics Research…

Analysis of PDEs · Mathematics 2021-11-05 Adel Khalfallah , Bojana Purtić , Miodrag Mateljević

The purpose of this paper is to study the Schwarz-Pick type inequalities for harmonic or pluriharmonic functions. By analogy with the generalized Khavinson conjecture, we first give some sharp estimates of the norm of harmonic functions…

Complex Variables · Mathematics 2021-10-05 Shaolin Chen , Hidetaka Hamada

In this paper, we study the concepts of normal functions and $\varphi$-normal functions in the framework of planar harmonic mappings. We establish the harmonic mapping counterpart of the well-known Zalcman-Pang lemma and as a consequence,…

Complex Variables · Mathematics 2025-06-24 Nikhil Bharti , Nguyen Van Thin

The most classical version of the Schwarz lemma involves the behavior at the origin of a bounded, holomorphic function on the disc. Pick's version of the Schwarz lemma allows one to move the origin to other points of the disc. In the…

Complex Variables · Mathematics 2010-01-13 Steven G. Krantz

Quantitative estimates are obtained for the (finite) valence of functions analytic in the unit disk with Schwarzian derivative that is bounded or of slow growth. A harmonic mapping is shown to be uniformly locally univalent with respect to…

Complex Variables · Mathematics 2007-07-16 Martin Chuaqui , Peter Duren , Brad Osgood

In this paper we prove a Schwarz lemma for harmonic mappings between the unit balls in real Euclidean spaces. Roughly speaking, our result says that under a harmonic mapping between the unit balls in real Euclidean spaces, the image of a…

Complex Variables · Mathematics 2013-04-10 Shaoyu Dai , Yifei Pan

We prove a version of the Schwarz lemma for holomorphic mappings from the unit disk into the symmetric product of a Riemann surface. Our proof is function-theoretic and self-contained. The main novelty in our proof is the use of the…

Complex Variables · Mathematics 2019-09-10 Jaikrishnan Janardhanan

We study the lemniscates of rational maps. We prove a reflection principle for the harmonic measure of rational lemniscates and we give estimates for their capacity and the capacity of their components. Also, we prove a version of Schwarz's…

Complex Variables · Mathematics 2015-10-29 Stamatis Pouliasis , Thomas Ransford

In this paper, we first establish the Schwarz-Pick lemma of higher-order and apply it to obtain a univalency criteria for planar harmonic mappings. Then we discuss distortion theorems, Lipschitz continuity and univalency of planar harmonic…

Complex Variables · Mathematics 2014-04-17 Shaolin Chen , Saminathan Ponnusamy , Antti Rasila , Xiantao Wang

We establish some Schwarz type Lemmas for mappings defined on the unit disk with bounded Laplacian. Then we apply these results to obtain boundary versions of the Schwarz lemma.

Complex Variables · Mathematics 2018-10-23 Miodrag Mateljević , Adel Khalfallah

Motivared by Carleman's proof of the isoperimetric inequality in the plane, we study some sharp integral inequalities for harmonic functions on the upper halfspace. We also derive the regularity for nonnegative solutions of the associated…

Analysis of PDEs · Mathematics 2007-05-23 Fengbo Hang , Xiaodong Wang , Xiaodong Yan

Assume that $p\in[1,\infty]$ and $u=P_{h}[\phi]$, where $\phi\in L^{p}(\mathbb{S}^{n-1},\mathbb{R}^n)$ and $u(0) = 0$. Then we obtain the sharp inequality $|u(x)|\le G_p(|x|)\|\phi\|_{L^{p}}$ for some smooth function $G_p$ vanishing at $0$.…

Complex Variables · Mathematics 2020-04-15 Jiaolong Chen , David Kalaj

In this paper, we study the $(s, C(s))$-Harnack inequality in a domain $G\subset \mathbb{R}^n$ for $s\in(0,1)$ and $C(s)\geq1$ and present a series of inequalities related to $(s, C(s))$-Harnack functions and the Harnack metric. We also…

Complex Variables · Mathematics 2024-12-11 Rahim Kargar

We prove a sharp Schwarz-type lemma for meromorphic functions with spherical derivative uniformly bounded away from zero. As a consequence we deduce an improved quantitative version of a recent normality criterion due to Grahl & Nevo and…

Complex Variables · Mathematics 2020-03-04 Richard Fournier , Daniela Kraus , Oliver Roth

In this paper, we investigate some properties on harmonic functions and solutions to Poisson equations. First, we will discuss the Lipschitz type spaces on harmonic functions. Secondly, we establish the Schwarz-Pick lemma for harmonic…

Complex Variables · Mathematics 2014-07-29 Sh. Chen , M. Mateljević , S. Ponnusamy , X. Wang

We establish a sharp norm estimate of the Schwarzian derivative for a function in the classes of convex functions introduced by Ma and Minda [Proceedings of the Conference on Complex Analysis, International Press Inc., 1992, 157-169]. As…

Complex Variables · Mathematics 2011-02-03 Stanisława Kanas , Toshiyuki Sugawa

We prove asymptotic estimates for the cross-ratio distortion with respect to a smooth or holomorphic function in terms of its Schwarz derivative.

Dynamical Systems · Mathematics 2009-01-09 Alexey Teplinsky

We prove two results related to the Schwarz lemma in complex geometry. First, we show that if the inequality in the Schwarz lemmata of Yau, Royden and Tosatti becomes equality at one point, then the equality holds on the whole manifold. In…

Differential Geometry · Mathematics 2022-02-15 Haojie Chen , Xiaolan Nie