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Related papers: Generalized harmonic Koebe functions

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In this article we prove Bohr inequalities for sense-preserving $K$-quasiconformal harmonic mappings defined in $\mathbb{D}$ and obtain the corresponding results for sense-preserving harmonic mappings by letting $K\to\infty$. One of the…

Complex Variables · Mathematics 2021-01-12 Bappaditya Bhowmik , Nilanjan Das

We construct sense-preserving univalent harmonic mappings which map the unit disk onto a domain which is convex in the horizontal direction, but with varying dilatation. Also, we obtain minimal surfaces associated with such harmonic…

Complex Variables · Mathematics 2015-08-04 YuePing Jiang , ZhiHong Liu , Saminathan Ponnusamy

The primary objective of this paper is to establish several sharp versions of improved Bohr inequalities, refined Bohr inequalities, and Bohr-Rogosinski inequalities for the class of $K$-quasiconformal sense-preserving harmonic mappings…

Complex Variables · Mathematics 2024-11-27 Vasudevarao Allu , Raju Biswas , Rajib Mandal

In this paper, we introduce formal sine functions whose coefficients are elements of a generalized harmonic algebra and investigate their properties corresponding to the classical addition formula and Pythagorean theorem. By taking their…

Number Theory · Mathematics 2025-06-18 Hanamichi Kawamura

Let $L_H$ denote the set of all normalized locally one-to-one and sense-preserving harmonic functions in the unit disc $\Delta$. It is well-known that every complex-valued harmonic function in the unit disc $\Delta$ can be uniquely…

Complex Variables · Mathematics 2014-10-14 Ikkei Hotta , Andrzej Michalski

We obtain the sharp upper and lower bounds for the growth and distortion of the analytic parts $h$ of orientation-preserving harmonic mappings $f=h+\overline g$ (normalized in the standard way) that map the unit disk onto a convex domain.

Complex Variables · Mathematics 2025-05-08 María J. Martín

A harmonic mapping is a univalent harmonic function of one complex variable. We define a family of harmonic mappings on the unit disk whose images are rotationally symmetric rosettes with $n$ cusps or n nodes, where $n \ge 3$. These…

Complex Variables · Mathematics 2021-06-08 Jane McDougall , Lauren Stierman

Estimating the coefficient functionals on various classes of holomorphic functions traditionally forms an important field of geometric complex analysis and its mathematical and physical applications. These coefficients reflect fundamental…

Complex Variables · Mathematics 2025-07-29 Samuel L. Krushkal

In this paper, we obtain coefficient criteria for a normalized harmonic function defined in the unit disk to be close-to-convex and fully starlike, respectively. Using these coefficient conditions, we present different classes of harmonic…

Complex Variables · Mathematics 2012-06-05 S. V. Bharanedhar , S. Ponnusamy

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

We show that, for many holomorphic function spaces on the unit disk, a continuous endomorphism that sends inner functions to inner functions is necessarily a weighted composition operator.

Complex Variables · Mathematics 2019-02-18 Javad Mashreghi , Thomas Ransford

In the present paper, we introduce a family of univalent harmonic functions, which map the unit disk onto domains convex in the direction of the imaginary axis. We find conditions for the linear combinations of mappings from this family to…

Complex Variables · Mathematics 2013-06-25 Raj Kumar , Sushma Gupta , Sukhjit Singh

We first construct the harmonic K-quasiconformal Koebe functions, filling a long-standing foundational gap in geometric function theory. This construction provides a unified parametric candidate extremal function framework for conformal…

Complex Variables · Mathematics 2026-03-31 Zhi-Gang Wang , Xiao-Yuan Wang , Antti Rasila , Jia-Le Qiu

We study noncommutative versions of holomorphic and harmonic functions on the unit disk.

Operator Algebras · Mathematics 2007-05-23 Slawomir Klimek

In this paper, we discuss the associated family of harmonic maps $\mathcal{F}: M \rightarrow G/K$ from a Riemann surface $M$ into inner symmetric spaces of compact or non-compact type which are either algebraic or totally symmetric. These…

Differential Geometry · Mathematics 2024-08-23 Josef F. Dorfmeister , Peng Wang

We study conjugate-type phenomena for complex-valued harmonic quasiregular mappings in the unit disk across three function space families: $Q(n,p,\alpha)$, $F(p,q,s)$, and the non-derivative $M(p,q,s)$. For a harmonic $K$-quasiregular…

Complex Variables · Mathematics 2026-01-13 Jihua Sun , Junming Liu , Zhi-Gang Wang

In the article the authors consider the class ${\mathcal H}_0$ of sense-preserving harmonic functions $f=h+\overline{g}$ defined in the unit disk $|z|<1$ and normalized so that $h(0)=0=h'(0)-1$ and $g(0)=0=g'(0)$, where $h$ and $g$ are…

Complex Variables · Mathematics 2015-06-02 Liulan Li , Saminathan Ponnusamy

Let $D$ be the open unit disc in the complex plane. We denote by $\mathbb{C}$ the set of complex numbers and consider any compact set $K$ which is disjoint from $D$ and which also has connected complement. Let $A(K)$ denote all the…

Complex Variables · Mathematics 2015-06-05 Nikos Tsirivas

In this paper, first we give a new generalization of the Bohr's inequality for the class of bounded analytic functions $\mathcal{B'}$ and for the class of sense-preserving $K$-quasiconformal harmonic mappings of the form $f=h+\overline{g},$…

Complex Variables · Mathematics 2021-04-14 Ramakrishnan Vijayakumar

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