scholarly journals Properties of a Class of -Harmonic Functions

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Elif Yaşar ◽  
Sibel Yalçın

A times continuously differentiable complex-valued function in a domain is -harmonic if satisfies the -harmonic equation , where is a positive integer. By using the generalized Salagean differential operator, we introduce a class of -harmonic functions and investigate necessary and sufficient coefficient conditions, distortion bounds, extreme points, and convex combination of the class.

2013 ◽  
Vol 2013 ◽  
pp. 1-11
Author(s):  
A. T. Oladipo ◽  
D. Breaz

We define and investigate a new subclass of Bazilevič type harmonic univalent functions using a linear operator. We investigated the harmonic structures in terms of its coefficient conditions, extreme points, distortion bounds, convolution, and convex combination. So, also, we discussed the subordination properties for the functions in this class.


2021 ◽  
Vol 26 (4) ◽  
pp. 491-500
Author(s):  
Hasan BAYRAM ◽  
Sibel Yalçın

We introduce and investigate classes of (p,q)-starlike harmonic univalent functions defined by subordination. We first obtained a coefficient characterization of these functions. We give necessary and sufficient convolution conditions, distortion bounds, compactness and extreme points for the (p,q)-starlike harmonic univalent with negative coefficients.


Author(s):  
Adnan Ghazy Alamoush

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 studied.


2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
M. K. Aouf ◽  
A. O. Moustafa ◽  
E. A. Adwan

We introduce a new class of multivalent harmonic functions defi…ned by Wright generalized hypergeometric function. Coefficient estimates, extreme points, distortion bounds, and convex combination for functions belonging to this class are obtained.


Filomat ◽  
2009 ◽  
Vol 23 (1) ◽  
pp. 91-101 ◽  
Author(s):  
A. Ebadian ◽  
A. Tehranchi

In this paper we have introduced two new classes HRp(?, ?, k, v),HRp(?, ?, k, v) of complex valued harmonic multivalent functions of the form f = h+g, where h and g are analytic in the unit disk ? = {z: |z| < 1} and f(z) satisfying the condition Re (1-?)Df+ ?(1-k)(Df)'+ ?k(Df)''> ? A sufficient coefficient condition for this function in the class HRp(?, ?, k, v) and a necessary and sufficient coefficient condition for the function f in the class HRp(?, ?, k, v) are determined. We investigate inclusion relations, distortion theorem, extreme points, convex combination and other interesting properties for these families. .


2019 ◽  
Vol 106 (120) ◽  
pp. 19-28
Author(s):  
Jacek Dziok ◽  
Sibel Yalçın ◽  
Şahsene Altınkaya

We introduce a new subclass of functions defined by multiplier differential operator and give coefficient bounds for these subclasses. Also, we obtain necessary and sufficient convolution conditions, distortion bounds and extreme points for these subclasses of functions.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Huda Aldweby ◽  
Maslina Darus

We study a class of complex-valued harmonic univalent functions using a generalized operator involving basic hypergeometric function. Precisely, we give a necessary and sufficient coefficient condition for functions in this class. Distortion bounds, extreme points, and neighborhood of such functions are also considered.


2010 ◽  
Vol 2010 ◽  
pp. 1-12 ◽  
Author(s):  
Khalifa Al-Shaqsi ◽  
Maslina Darus ◽  
Olubunmi Abidemi Fadipe-Joseph

We define and investigate a new subclass of Salagean-type harmonic univalent functions. We obtain coefficient conditions, extreme points, distortion bounds, convolution, and convex combination for the above subclass of harmonic functions.


2010 ◽  
Vol 41 (3) ◽  
pp. 261-269 ◽  
Author(s):  
K. K. Dixit ◽  
Saurabh Porwal

Complex-valued harmonic functions that are univalent and sense-preserving in the open unit disc $U$ can be written in the form $f=h+\bar g$, where $h$ and $g$ are analytic in $U$. In this paper authors introduce the class, $R_H(\beta)$, $(1<\beta \le 2)$ consisting of harmonic univalent functions $f=h+\bar g$, where $h$ and $g$ are of the form $ h(z)=z+ \sum_{k=2}^\infty |a_k|z^k $ and $ g(z)= \sum_{k=1}^\infty |b_k| z^k $ for which $\Re\{h'(z)+g'(z)\}<\beta$. We obtain distortion bounds extreme points and radii of convexity for functions belonging to this class and discuss a class  preserving integral operator. We also show that class studied in this paper is closed under convolution and convex combinations.


Author(s):  
Deepali Khurana ◽  
Raj Kumar ◽  
Sibel Yalcin

We define two new subclasses, $HS(k, \lambda, b, \alpha)$ and \linebreak $\overline{HS}(k, \lambda, b, \alpha)$, of univalent harmonic mappings using multiplier transformation. We obtain a sufficient condition for harmonic univalent functions to be in $HS(k,\lambda,b,\alpha)$ and we prove that this condition is also necessary for the functions in the class $\overline{HS} (k,\lambda,b,\alpha)$. We also obtain extreme points, distortion bounds, convex combination, radius of convexity and Bernandi-Libera-Livingston integral for the functions in the class $\overline{HS}(k,\lambda,b,\alpha)$.


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