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By considering a fixed point in unit disk $\Delta$, a new class of univalent convex functions is defined. Coefficient inequalities, integral operator and extreme points of this class are obtained.

Complex Variables · Mathematics 2009-04-23 Sh. Najafzadeh , M. Eshaghi Gordji , A. Ebadian

In this paper, we define a new subclass of $k$-uniformly starlike functions of order $\gamma,\ (0\leq\gamma<1)$ by using certain generalized $q$-integral operator. We explore geometric interpretation of the functions in this class by…

Complex Variables · Mathematics 2021-01-14 Om Ahuja , Asena Çetinkaya , Naveen Kumar Jain

We obtain new uniqueness theorems for harmonic functions defined on the unit disc or in the half plane. These results are applied to obtain new resolvent descriptions of spectral subspaces of polynomially bounded groups of operators on…

Complex Variables · Mathematics 2010-03-16 Alexander Borichev , Yuri Tomilov

In this paper, we introduce a new subclass of close-to-convex harmonic functions. We present a sufficient coefficient condition for a function to be a member of this class. Furthermore, we establish a distortion theorem. These results lay…

Complex Variables · Mathematics 2025-02-10 Serkan Çakmak , Sibel Yalçin

In this paper, by making use of a certain family of fractional derivative operators in the complex domain, we introduce and investigate a new subclass $\mathcal{P}_{\tau,\mu}(k,\delta,\gamma)$ of analytic and univalent functions in the open…

Complex Variables · Mathematics 2015-11-06 Zainab Esa , H. M. Srivastava , Adem Kilicman , Rabha W. Ibrahim

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

Operator Algebras · Mathematics 2007-05-23 Slawomir Klimek

The aim of this paper is to obtain the Schwarz-Pick type inequality for $\alpha$-harmonic functions $f$ in the unit disk and get estimates on the coefficients of $f$. As an application, a Landau type theorem of $\alpha$-harmonic functions…

Complex Variables · Mathematics 2017-05-30 Peijin Li , Xiantao Wang , Qianhong Xiao

The purpose of the present paper is to establish connections between various subclasses of analytic univalent functions by applying certain convolution operator involving Touchard polynomials. To be more precise, we investigate such…

Complex Variables · Mathematics 2020-07-13 G. Murugusundaramoorthy , Saurabh Porwal

n this article we consider functions meromorphic in the unit disk. We give an elementary proof for a condition that is sufficient for the univalence of such functions which also contains some known results. We include few open problems for…

Complex Variables · Mathematics 2019-05-07 See Keong Lee , Saminathan Ponnusamy , Karl-Joachim Wirths

In this paper we determine the disks $|z|<r\le1$ where for different classes of univalent functions, we have the property $${\rm Re}\left\{2\frac{zf'(z)}{f(z)}-\frac{z f''(z)}{f'(z)}\right\}>0\qquad (|z|<r).$$

Complex Variables · Mathematics 2020-12-15 Nikola Tuneski , Milutin Obradović

In this study, a subclass of an univalent function with negative coefficients which is defined by a new general Linear operator have been introduced. The sharp results for coefficients estimators, distortion and closure bounds, Hadamard…

Complex Variables · Mathematics 2020-05-15 Mazin Sh. Mahmoud , Abdul Rahman S. Juma , Raheam A. Mansor Al-Saphory

In this paper, we find the coefficient bounds using symmetric Toeplitz determinants for the functions belonging to the subclass $R(q)$.

Complex Variables · Mathematics 2017-08-14 Nanjundan Magesh , Şahsene Altınkaya , Sibel Yalçın

In this paper, we introduce a new subclass of harmonic functions $f=s+\overline{t}$ in the open unit disk $U =\left \{ z\in C:\left \vert z\right \vert <1\right \} $ satisfying ${\text{Re}}\left[ \gamma s^{\prime }(z)+\delta zs^{\prime…

Complex Variables · Mathematics 2021-07-09 Serkan Çakmak , Elif Yaşar , Sibel Yalçın

Let ${\mathcal S}$ be the class of all functions $f$ that are analytic and univalent in the unit disk $\ID$ with the normalization $f(0)=f'(0)-1=0$. Let $\mathcal{U} (\lambda)$ denote the set of all $f\in {\mathcal S}$ satisfying the…

Complex Variables · Mathematics 2011-12-06 M. Obradović , S. Ponnusamy

Let u be a subharmonic function in D={|z|<1}. There exist an absolute constant C and an analytic function f in D such that \int_D |u(z)-log|f(z)|| dm(z)<C where m denotes the plane Lebesgue measure. We also consider uniform approximation.

Complex Variables · Mathematics 2008-07-08 Igor Chyzhykov

The problem on estimate of the Koebe radius for univalent harmonic mappings of the unit disk $\mathbb D=\{z\in\mathbb C : |z|<1\}$ is considered. For a subclass of harmonic mappings with the standard normalization and a certain growth…

Complex Variables · Mathematics 2025-05-06 Mikhail Borovikov

Introducing a new method we give sharp estimates of the Hermitian Toepliz determinants of third order for the class $\mathcal{S}$ of functions univalent in the unit disc. The new approach is also illustrated on some subclasses of the class…

Complex Variables · Mathematics 2021-04-23 Milutin Obradović , Nikola Tuneski

We prove the stronger version of Harnack's inequality for positive harmonic functions defined on the unit disc.

Complex Variables · Mathematics 2025-01-20 Marek Svetlik

The object of this paper is to study relationship between successive coefficients of some subclasses of the class of univalent functions in the unit disk. the result obtained is sharp, and is used to provide a new, short proof of the…

Complex Variables · Mathematics 2010-04-21 K. O. Babalola

This paper provides the foundations of quantum Clifford analysis in $q$-commutative variables with symmetric difference operators. We consider a $q$-Dirac operator on the quantum Euclidean space that factorizes the $U_q(\frak{o})$-invariant…

Complex Variables · Mathematics 2025-04-15 Swanhild Bernstein , Martha Lina Zimmermann , Baruch Schneider