Harmonic mappings related to the m-fold starlike functions

2015 ◽  
Vol 267 ◽  
pp. 805-809
Author(s):  
Melike Aydoğan ◽  
Yaşar Polatoğlu ◽  
Yasemin Kahramaner
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 $\overline{HS}(k,\lambda,b,\alpha)$.


2014 ◽  
Vol 270 ◽  
pp. 564-570
Author(s):  
Yasemin Kahramaner ◽  
Yaşar Polatog˜lu ◽  
Melike Aydog˜an

2014 ◽  
Author(s):  
Durdane Varol ◽  
Melike Aydoğan ◽  
Yaşar Polatoğlu

Author(s):  
Maisarah Haji Mohd ◽  
Maslina Darus

Motivated by the success of the Janowski starlike function, we consider here closely related functions for log-harmonic mappings of the form defined on the open unit disc . The functions are in the class of the generalized Janowski starlike log-harmonic mapping, , with the functional in the class of the generalized Janowski starlike functions, . By means of these functions, we obtained results on the generalized Janowski close-to-starlike log-harmonic mappings, .


2014 ◽  
Vol 43 (12) ◽  
pp. 1961-1964
Author(s):  
Yasemin Kahramaner ◽  
Yaşar Polatoğlu

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Mengkun Zhu ◽  
Xinzhong Huang

Some sharp estimates of coefficients, distortion, and growth for harmonic mappings with analytic parts convex or starlike functions of orderβare obtained. We also give area estimates and covering theorems. Our main results generalise those of Klimek and Michalski.


2020 ◽  
Vol 61(12) (2) ◽  
pp. 381-392
Author(s):  
Gangadhara Murugusundaramoorthy ◽  
◽  
Janusz Sokol ◽  
Keyword(s):  

Author(s):  
Deepali Khurana ◽  
Sushma Gupta ◽  
Sukhjit Singh

In the present article, we consider a class of univalent harmonic mappings, $\mathcal{C}_{T} = \left\{ T_{c}[f] =\frac{f+czf'}{1+c}+\overline{\frac{f-czf'}{1+c}}; \; c>0\;\right\}$ and $f$ is convex univalent in $\mathbb{D}$, whose functions map the open unit disk $\mathbb{D}$ onto a domain convex in the direction of the imaginary axis. We estimate coefficient, growth and distortion bounds for the functions of the same class.


2020 ◽  
Vol 70 (4) ◽  
pp. 849-862
Author(s):  
Shagun Banga ◽  
S. Sivaprasad Kumar

AbstractIn this paper, we use the novel idea of incorporating the recently derived formula for the fourth coefficient of Carathéodory functions, in place of the routine triangle inequality to achieve the sharp bounds of the Hankel determinants H3(1) and H2(3) for the well known class 𝓢𝓛* of starlike functions associated with the right lemniscate of Bernoulli. Apart from that the sharp bound of the Zalcman functional: $\begin{array}{} |a_3^2-a_5| \end{array}$ for the class 𝓢𝓛* is also estimated. Further, a couple of interesting results of 𝓢𝓛* are also discussed.


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