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In this article, we provide some necessary and sufficient coefficients conditions for a harmonic mapping to be hereditarily spirallike. Also, we give growth estimate for certain harmonic hereditarily spirallike mappings. Moreover, we…

Complex Variables · Mathematics 2023-09-06 Md Firoz Ali , Sushil Pandit

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 will provide sufficient conditions for the shifted hypergeometric function $z_2F_1(a,b;c;z)$ to be a member of a specific subclass of starlike functions in terms of the complex parameters $a,b$ and $c.$ For example, we study starlikeness…

Complex Variables · Mathematics 2017-04-27 Toshiyuki Sugawa , Li-Mei Wang

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

A normalized univalent function is uniformly convex if it maps every circular arc contained in the open unit disk with center in it into a convex curve. This article surveys recent results on the class of uniformly convex functions and on…

Complex Variables · Mathematics 2011-08-23 R. M. Ali , 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 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

In this note we investigate the inclusion relationship between the class of strongly starlike functions of order alpha and type beta and the class of strongly convex functions of order alpha and type beta which are subclass of normalized…

Complex Variables · Mathematics 2009-11-24 Ikkei Hotta , Mamoru Nunokawa

We investigate harmonic mappings $f=h+\bar{g}$ defined in the unit disk, where $g$ and $h$ satisfy certain prescribed conditions and the analytic part $h$ belongs to the Ma and Minda class of starlike functions. Certain sharp radius results…

Complex Variables · Mathematics 2022-08-02 Kamaljeet Gangania

In this note, we consider certain logharmonic mappings in the unit disk $\mathbb{D}=\{z\in\mathbb{C}:|z|<1\}.$ Next, we obtain sharp bound of pre-Schwarzian norm of such logharmonic mappings in the unit disk. Then we discuss growth theorem…

Complex Variables · Mathematics 2025-05-21 Sushil Pandit

This paper reports on constructive approximation methods for three classes of holomorphic functions on the unit disk which are closely connected each other: the class of starlike and spirallike functions, the class of semigroup generators,…

Complex Variables · Mathematics 2007-05-23 Mark Elin , David Shoikhet , Lawrence Zalcman

Let $\lambda$ be a real number with $-\pi/2<\lambda<\pi/2.$ In order to study $\lambda$-spirallike functions, it is natural to measure the angle according to $\lambda$-spirals. Thus we are led to the notion of $\lambda$-argument. This fits…

Complex Variables · Mathematics 2010-03-09 Yong Chan Kim , Toshiyuki Sugawa

For given non-negative real numbers $\alpha_k$ with $ \sum_{k=1}^{m}\alpha_k =1$ and normalized analytic functions $f_k$, $k=1,\dotsc,m$, defined on the open unit disc, let the functions $F$ and $F_n$ be defined by $…

Complex Variables · Mathematics 2022-01-06 Somya Malik , Vaithiyanathan Ravichandran

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

We consider the family of all analytic and univalent functions in the unit disk of the form $f(z)=z+a_2z^2+a_3z^3+\cdots$. Our objective in this paper is to estimate the difference of the moduli of successive coefficients, that is $\big |…

Complex Variables · Mathematics 2019-03-26 Vibhuti Arora , Saminathan Ponnusamy , Swadesh Kumar Sahoo

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 define a new family of symmetric functions which are affine analogues of Stanley symmetric functions. We establish basic properties of these functions including symmetry, dominance and conjugation. We conjecture certain positivity…

Combinatorics · Mathematics 2007-05-23 Thomas Lam

The primary aim of this paper is to characterize the uniformly locally univalent harmonic mappings in the unit disk. Then, we obtain sharp distortion, growth and covering theorems for one parameter family ${\mathcal B}_{H}(\lambda)$ of…

Complex Variables · Mathematics 2016-01-07 S. Ponnusamy , J. Qiao , X. Wang

It is proved that harmonic functions are characterized by harmonicity of their spherical means, for which purpose the iterated spherical means are used. The similar characterization of solutions to the modified Helmholtz equation…

Analysis of PDEs · Mathematics 2021-10-12 Nikolay Kuznetsov

In the present paper, we introduce a new subclass of harmonic functions in the unit disc U defined by using the generalized Mittag-Leffler type functions. Coefficient conditions, extreme points, distortion bounds, convex combination are…

Complex Variables · Mathematics 2019-01-25 Adnan Ghazy AlAmoush
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