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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

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

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

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

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

In the present paper, we derive several conditions of linear combinations and convolutions of harmonic mappings to be univalent and convex in one direction, one of them gives a partial answer to an open problem proposed by Dorff. The…

Complex Variables · Mathematics 2021-11-02 Zhi-Gang Wang , Lei Shi , Yue-Ping Jiang

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

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

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

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

Let ${\mathcal S^0}(H_{\gamma})$ denote the class of all univalent, harmonic, sense-preserving and normalized mappings $f$ of the unit disk $\ID$ onto the slanted half-plane $H_\gamma :=\{w:\,{\rm Re\,}(e^{i\gamma}w) >-1/2\}$ with an…

Complex Variables · Mathematics 2012-06-21 Liulan Li , S. Ponnusamy

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

Dorff et al. [4], proved that the harmonic convolution of right half-plane mapping with dilatation -z and mapping f_\beta = h_\beta + \bar{g}_\beta, where f_\beta is obtained by shearing of analytic vertical strip mapping, with dilatation…

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

Let f_\beta = h_\beta+\bar{g}_\beta and F_a = H_a +\bar{G}_a be harmonic mappings obtained by shearing of analytic mappings h_\beta +g_\beta = 1/(2i\sin\beta)log((1 + ze^{i\beta})/(1 + ze^{-i\beta})), 0<\beta<\pi and H_a+G_a = z/(1-z),…

Complex Variables · Mathematics 2013-07-25 Raj Kumar , Sushma Gupta , Sukhjit Singh , Michael Dorff

In 1984, Clunie and Sheil-Small proved that a sense-preserving harmonic function whose analytic part is convex, is univalent and close-to-convex. In this paper, certain cases are discussed under which the conclusion of this result can be…

Complex Variables · Mathematics 2013-11-12 Sumit Nagpal , V. Ravichandran

In this paper, we introduces and undertake as a systematical investigation of the class $\mathcal{P}_{\mathcal{H}}^{0}(\alpha,M)$ of normalized harmonic mappings $f = h + \overline{g}$ in the unit disk $\mathbb{D}$, defined by the…

Complex Variables · Mathematics 2026-04-13 Vasudevarao Allu , Raju Biswas , Rajib Mandal

We determine completely the analytic functions $\varphi$ in the unit disk $\mathbb D$ such that for all (normalized) orientation-preserving harmonic mappings $f=h+\overline g$ produced by the shear construction with $h+g=\varphi$, the…

We establish two-point distortion theorems for sense-preserving planar harmonic mappings $f=h+\overline{g}$ which satisfies the univalence criteria in the unit disc such that, Becker's and Nehari`s harmonic version. In addition, we find the…

Complex Variables · Mathematics 2022-08-08 Víctor Bravo , Rodrigo Hernández , Osvaldo Venegas

For $\alpha > -1$ and $\beta >0, $ let $\mathcal{B}_{\mathcal{H}}^0(\alpha, \beta)$ denote the class of sense preserving harmonic mappings $f=h+\overline{g}$ in the open unit disk $\mathbb{D}$ satisfying $|zh''(z)+\alpha(h'(z)-1)|\leq…

Complex Variables · Mathematics 2021-03-19 Manivannan Mathi , Jugal Kishore Prajapat

Let $\mathcal{S}_H^0$ denote the class of all functions $f(z)=h(z)+\overline{g(z)}=z+\sum^\infty_{n=2} a_nz^n +\overline{\sum^\infty_{n=2} b_nz^n}$ that are sense-preserving, harmonic and univalent in the open unit disk $|z|<1$. The…

Complex Variables · Mathematics 2017-03-08 Saminathan Ponnusamy , Anbareeswaran Sairam Kaliraj , Victor V. Starkov
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