scholarly journals Coefficient Estimates for a New Subclass of Analytic and Bi-Univalent Functions Defined by Hadamard Product

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Serap Bulut
Keyword(s):  
Unit Disk ◽  
Hadamard Product ◽  
Univalent Functions ◽  
Open Unit ◽  
Open Unit Disk ◽  
Coefficient Estimates

We introduce and investigate a new general subclass ℋΣλ,μ(φ;Θ) of analytic and bi-univalent functions in the open unit disk U. For functions belonging to this class, we obtain estimates on the first two Taylor-Maclaurin coefficients |a2| and |a3|.

scholarly journals Coefficient estimates for a new subclass of analytic and bi-univalent functions by Hadamard product

2021 ◽  
Vol 39 (2) ◽  
pp. 87-104
Author(s):  
Ebrahim Analouei Adegani ◽  
Ahmad Zireh ◽  
Mostafa Jafari
Keyword(s):  
Unit Disk ◽  
Hadamard Product ◽  
Univalent Functions ◽  
Upper Bounds ◽  
Open Unit ◽  
Open Unit Disk ◽  
Coefficient Estimates

In this work, we introduce a new subclas of bi-univalent functions which is defined by Hadamard product andsubordination in the open unit disk. and find upper bounds for the second and third coefficients for functions in this new subclass. Further, we generalize and improve some of the previously published results.

Coefficient Estimates for Certain Subclasses of m-Fold Symmetric Bi-univalent Functions Associated with Pseudo-Starlike Functions

2021 ◽  
pp. 209-223
Author(s):  
Timilehin G. Shaba ◽  
Amol B. Patil
Keyword(s):  
Unit Disk ◽  
Univalent Function ◽  
Univalent Functions ◽  
Starlike Functions ◽  
Function Class ◽  
Open Unit ◽  
Open Unit Disk ◽  
Coefficient Estimates

In the present investigation, we introduce the subclasses $\varLambda_{\Sigma}^{m}(\eta,\leftthreetimes,\phi)$ and $\varLambda_{\Sigma}^{m}(\eta,\leftthreetimes,\delta)$ of \textit{m}-fold symmetric bi-univalent function class $\Sigma_m$, which are associated with the pseudo-starlike functions and defined in the open unit disk $\mathbb{U}$. Moreover, we obtain estimates on the initial coefficients $|b_{m+1}|$ and $|b_{2m+1}|$ for the functions belong to these subclasses and identified correlations with some of the earlier known classes.

Coefficient Estimates and Quasi-Subordination Properties Associated with Certain Subclasses of Analytic and Bi-Univalent Functions

2015 ◽  
Vol 65 (3) ◽  
Author(s):  
S. P. Goyal ◽  
Rakesh Kumar
Keyword(s):  
Analytic Function ◽  
Unit Disk ◽  
Univalent Functions ◽  
Open Unit ◽  
Open Unit Disk ◽  
Coefficient Estimates

AbstractIn the present paper, we obtain the estimates on initial coefficients of normalized analytic function f in the open unit disk with f and its inverse g = f

scholarly journals The Pre-Schwarzian Norm Estimate for Analytic Concave Functions

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Young Jae Sim ◽  
Oh Sang Kwon
Keyword(s):  
Unit Disk ◽  
Hypergeometric Functions ◽  
Hadamard Product ◽  
Univalent Functions ◽  
Open Unit ◽  
Opening Angle ◽  
Sufficient Condition ◽  
Open Unit Disk ◽  
Concave Functions ◽  
Norm Estimate

LetDdenote the open unit disk and letSdenote the class of normalized univalent functions which are analytic inD. LetCo(α)be the class of concave functionsf∈S, which have the condition that the opening angle off(D)at infinity is less than or equal toπα,α∈(1,2]. In this paper, we find a sufficient condition for the Gaussian hypergeometric functions to be in the classCo(α). And we define a classCo(α,A,B),(-1≤B<A≤1), which is a subclass ofCo(α)and we find the set of variabilities for the functional(1-|z|2)(f″(z)/f′(z))forf∈Co(α,A,B). This gives sharp upper and lower estimates for the pre-Schwarzian norm of functions inCo(α,A,B). We also give a characterization for functions inCo(α,A,B)in terms of Hadamard product.

scholarly journals Some general coefficient estimates for a new class of analytic and bi-univalent functions defined by a linear combination

Filomat ◽  
2018 ◽  
Vol 32 (4) ◽  
pp. 1313-1322 ◽  
Author(s):  
H.M. Srivastava ◽  
Müge Sakar ◽  
Güney Özlem
Keyword(s):  
Linear Combination ◽  
Unit Disk ◽  
Univalent Function ◽  
Univalent Functions ◽  
Function Class ◽  
Open Unit ◽  
Faber Polynomials ◽  
Open Unit Disk ◽  
Coefficient Estimates ◽  
New Class

In the present paper, we introduce and investigate a new class of analytic and bi-univalent functions f (z) in the open unit disk U. For this purpose, we make use of a linear combination of the following three functions: f(z)/z, f'(z) and z f''(z) for a function belonging to the normalized univalent function class S. By applying the technique involving the Faber polynomials, we determine estimates for the general Taylor-Maclaurin coefficient of functions belonging to the analytic and bi-univalent function class which we have introduced here. We also demonstrate the not-too-obvious behaviour of the first two Taylor-Maclaurin coefficients of such functions.

scholarly journals Initial coefficient estimates for a classes of m-fold symmetric bi-univalent functions involving Mittag-Leffler function

2020 ◽  
Vol 24 (2) ◽  
pp. 51-61
Author(s):  
Abbas Wanas ◽  
Huo Tang
Keyword(s):  
Unit Disk ◽  
Univalent Functions ◽  
Open Unit ◽  
Open Unit Disk ◽  
Coefficient Estimates ◽  
Initial Coefficient ◽  
Special Cases

The main object of the present paper is to use Mittag-Leffler function to introduce and study two new classes RSm(g, l, e, d, t ; a) and R * Sm(g, l, e, d, t ; b) of Sm consisting of analytic and m-fold symmetric bi-univalent functions defined in the open unit disk U. Also, we determine the estimates on the initial coefficients |am+1| and |a2m+1| for functions in each of these new classes. Furthermore, we indicate certain special cases for our results.

Faber polynomial coefficient estimates for subclass of bi-univalent functions defined by quasi-subordinate

2018 ◽  
Vol 68 (2) ◽  
pp. 369-378 ◽  
Author(s):  
Ahmad Zireh ◽  
Ebrahim Analouei Adegani ◽  
Mahmood Bidkham
Keyword(s):  
Unit Disk ◽  
Univalent Functions ◽  
Upper Bounds ◽  
Polynomial Expansion ◽  
Polynomial Coefficient ◽  
Open Unit ◽  
Open Unit Disk ◽  
Coefficient Estimates ◽  
Faber Polynomial

Abstract In this paper, we use the Faber polynomial expansion to find upper bounds for |an| (n ≥ 3) coefficients of functions belong to classes $\begin{array}{} H_{q}^{\Sigma}(\lambda,h),\, ST_{q}^{\Sigma}(\alpha,h)\,\text{ and} \,\,M_{q}^{\Sigma}(\alpha,h) \end{array}$ which are defined by quasi-subordinations in the open unit disk 𝕌. Further, we generalize some of the previously published results.

scholarly journals Coefficient estimates for certain subclasses of analytic and bi-univalent functions

Filomat ◽  
2015 ◽  
Vol 29 (2) ◽  
pp. 351-360 ◽  
Author(s):  
Yong Sun ◽  
Yue-Ping Jiang ◽  
Antti Rasila
Keyword(s):  
Unit Disk ◽  
Analytic Functions ◽  
Univalent Functions ◽  
Upper Bounds ◽  
Open Unit ◽  
Open Unit Disk ◽  
Coefficient Estimates

For ? ? 0 and 0 ? ? < 1 < ?, we denote by K(?,?,?) the class of normalized analytic functions satisfying the two sided-inequality ? < K (Zf'(z)/f(z) + z2f''(z)/f(z))<? (z ? U), where U is the open unit disk. Let K? (?, ?, ?) be the class of bi-univalent functions such that f and its inverse f-1 both belong to the class K(?, ?, ?). In this paper, we establish bounds for the coefficients, and solve the Fekete-Szeg? problem, for the class K((?,?,?). Furthermore, we obtain upper bounds for the first two Taylor-Maclaurin coefficients of the functions in the class K? (?,?,?)

scholarly journals Coefficient estimates for a general subclass of analytic and bi-univalent functions

Filomat ◽  
2013 ◽  
Vol 27 (5) ◽  
pp. 831-842 ◽  
Author(s):  
Harim Srivastava ◽  
Serap Bulut ◽  
Murat Ҫaǧlar ◽  
Nihat Yağmur
Keyword(s):  
Unit Disk ◽  
Univalent Functions ◽  
Open Unit ◽  
Open Unit Disk ◽  
Coefficient Estimates

In this paper, we introduce and investigate an interesting subclass N?h,p (?, ?) of analytic and bi-univalent functions in the open unit disk U. For functions belonging to the class N?h,p (?, ?), we obtain estimates on the first two Taylor-Maclaurin coefficients |a2| and |a3|. The results presented in this paper would generalize and improve some recent works of ?a?lar et al. [3], Xu et al. [10], and other authors.

scholarly journals Coefficient estimates for some subclasses of bi-univalent functions related to m-fold symmetry

2019 ◽  
Vol 11 (2) ◽  
pp. 81-86
Author(s):  
Waggas Galib Atshan ◽  
Salwa Kalf Kazim
Keyword(s):  
Unit Disk ◽  
Univalent Functions ◽  
Open Unit ◽  
Open Unit Disk ◽  
Coefficient Estimates ◽  
Special Cases

The purpose of present paper is to introduce and  investigate two new subclasses    and  of analytic and m-fold symmetric bi- univalent functions in the  open unit disk . Among other results belonging to these subclasses upper coefficients bounds   and  are obtained in this study. Certain special cases are also indicated .  

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