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Dorff, proved in [2] that the convolution of two harmonic right-half plane mappings is convex in the direction of real axis provided that the convolution is locally univalent and sense preserving. Later, it was shown in [3] that the…

Complex Variables · Mathematics 2013-04-24 Raj Kumar , Michael Dorff , Sushma Gupta , Sukhjit Singh

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

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

The first author proved that the harmonic convolution of a normalized right half-plane mapping with either another normalized right half-plane mapping or a normalized vertical strip mapping is convex in the direction of the real axis.…

Complex Variables · Mathematics 2009-03-10 Michael Dorff , Maria Nowak , Magdalena Woloszkiewicz

Let $\mathcal{H}$ denote the class of all complex-valued harmonic functions $f$ in the open unit disk normalized by $f(0)=0=f_{z}(0)-1=f_{\bar{z}}(0)$, and let $\mathcal{A}$ be the subclass of $\mathcal{H}$ consisting of normalized analytic…

Complex Variables · Mathematics 2013-02-26 Sumit Nagpal , V. Ravichandran

In this paper, we consider the convolutions of slanted half-plane mappings and strip mappings and generalize related results in general settings. We also consider a class of harmonic mappings containing slanted half-plane mappings and strip…

Complex Variables · Mathematics 2019-09-30 Liulan Li , Saminathan Ponnusamy

For $k=1,2$, let $f_k=h_k+\overline{g_k}$ be normalized harmonic right half-plane or vertical strip mappings. We consider the convex combination $\hat{f}=\eta f_1+(1-\eta)f_2 =\eta h_1+(1-\eta)h_2 +\overline{\overline{\eta}…

Complex Variables · Mathematics 2020-12-18 Subzar Beig , V. Ravichandran

In this paper using $q$ calculus operator we obtain some sufficient conditions on $f_1$ and $f_2$ so that their linear combination $% f=tf_{1}+(1-t)f_{2},\ t\in \left[ 0,1\right] $, is univalent and convex in the direction of the real axis.…

Complex Variables · Mathematics 2021-08-11 Omendra Mishra , Saurabh Porwal

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

Dorff et al. \cite{DN} formulated a question concerning the convolution of two right half-plane mappings, where the normalization of the functions was considered incorrectly. In this paper, we have reformulated the open problem in correct…

Complex Variables · Mathematics 2019-05-22 Liulan Li , Saminathan Ponnusamy

Let $\ast$ and $\widetilde {\ast}$ denote the convolution of two analytic maps and that of an analytic map and a harmonic map respectively. Pokhrel [1] proved that if $f = h+\overline{g}$ is a harmonic map convex in the direction of…

Complex Variables · Mathematics 2014-01-03 Raj Kumar , Sushma Gupta , Sukhjit Singh

In this article, we determine the radius of univalence of sections of normalized univalent harmonic mappings for which the range is convex (resp. starlike, close-to-convex, convex in one direction). Our result on the radius of univalence of…

Complex Variables · Mathematics 2017-01-24 Saminathan Ponnusamy , Anbareeswaran Sairam Kaliraj , Victor V. Starkov

We consider the convolution of half-plane harmonic mappings with respective dilatations $(z+a)/(1+az)$ and $e^{i\theta}z^{n}$, where $-1<a<1$ and $\theta\in\mathbb{R},n\in\mathbb{N}$. We prove that such convolutions are locally univalent…

Complex Variables · Mathematics 2016-09-20 Zhihong Liu , Saminathan Ponnusamy

In this paper, we prove necessary and sufficient conditions for a sense-preserving harmonic function to be absolutely convex in the open unit disk. We also estimate the coefficient bound and obtain growth, covering and area theorems for…

Complex Variables · Mathematics 2016-05-10 Saminathan Ponnusamy , Anbareeswaran Sairam Kaliraj , Victor V. Starkov

We show that the convolution of the harmonic function $f=h+\bar{g}$, where $h(z)+{e}^{-2{i}\gamma}g(z)=z/(1-{e}^{{i}\gamma}z)$ having analytic dilatation ${e}^{{i}\theta} z^n (0\leq\theta<2\pi)$, with the mapping…

Complex Variables · Mathematics 2017-03-13 Subzar Beig , V. Ravichandran

The hereditary property of convexity and starlikeness for conformal mappings does not generalize to univalent harmonic mappings. This failure leads us to the notion of fully starlike and convex mappings of order \alpha, (0\leq \alpha<1). A…

Complex Variables · Mathematics 2012-07-18 Sumit Nagpal , V. Ravichandran

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

We construct equivariant harmonic maps between cohomogeneity one manifolds.

Differential Geometry · Mathematics 2026-02-05 Anna Siffert

We investigate the univalency and the directional convexity of the convolution $\phi\tilde{*}f=\phi*h+\overline{\phi*g}$ of the harmonic mapping $f=h+\bar{g}$ with a mapping $\phi$ whose convolution with the mapping…

Complex Variables · Mathematics 2017-03-13 Subzar Beig , V. Ravichandran

The convolution properties are discussed for the complex-valued harmonic functions in the unit disk $\mathbb{D}$ constructed from the harmonic shearing of the analytic function $\phi(z):=\int_0^z…

Complex Variables · Mathematics 2017-03-13 Subzar Beig , V. Ravichandran
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