distortion theorem
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Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1840
Author(s):  
Lei Shi ◽  
Bakhtiar Ahmad ◽  
Nazar Khan ◽  
Muhammad Ghaffar Khan ◽  
Serkan Araci ◽  
...  

By making use of the concept of basic (or q-) calculus, many subclasses of analytic and symmetric q-starlike functions have been defined and studied from different viewpoints and perspectives. In this article, we introduce a new class of meromorphic multivalent close-to-convex functions with the help of a q-differential operator. Furthermore, we investigate some useful properties such as sufficiency criteria, coefficient estimates, distortion theorem, growth theorem, radius of starlikeness, and radius of convexity for this new subclass.


Mathematics ◽  
2021 ◽  
Vol 9 (15) ◽  
pp. 1812
Author(s):  
Hari M. Srivastava ◽  
Nazar Khan ◽  
Shahid Khan ◽  
Qazi Zahoor Ahmad ◽  
Bilal Khan

In this paper, we introduce a new class of harmonic univalent functions with respect to k-symmetric points by using a newly-defined q-analog of the derivative operator for complex harmonic functions. For this harmonic univalent function class, we derive a sufficient condition, a representation theorem, and a distortion theorem. We also apply a generalized q-Bernardi–Libera–Livingston integral operator to examine the closure properties and coefficient bounds. Furthermore, we highlight some known consequences of our main results. In the concluding part of the article, we have finally reiterated the well-demonstrated fact that the results presented in this article can easily be rewritten as the so-called (p,q)-variations by making some straightforward simplifications, and it will be an inconsequential exercise, simply because the additional parameter p is obviously unnecessary.


2021 ◽  
Vol 2 (18) ◽  
pp. 60-76
Author(s):  
Salma Faraj Ramadan ◽  

In the present paper, we introduce the class A of p-valent analytic functions in the open unit disk We investigate some inclusion properties, coefficient bounds, distortion theorem, -neighborhoods and partial sums. Also we obtain integral representation, weighted and arithmetic mean.


2021 ◽  
Vol 73 (2) ◽  
pp. 151-159
Author(s):  
Deguang Zhong ◽  
Wenjun Yuan

UDC 517.51 We study the hyperbolically Lipschitz continuity, Euclidean and hyperbolic area distortion theorem,  and coefficient estimate for the classes of -quasiconformal harmonic mappings from the unit disk onto itself.


Author(s):  
Timilehin G. Shaba ◽  
Abd'gafar T. Tiamiyu ◽  
Ismaila O. Ibrahim ◽  
Abdullahi A. Ibrahim

In this paper we introduce a new subclass $\mathcal{R}^*(p,g,\psi,\varrho,\beta,\phi,\gamma,\zeta)$ of $p$-valent functions with negative coefficient defined by Hadamard product associated with a generalized differential operator. Radii of close-to-convexity, starlikeness and convexity of the class $\mathcal{R}^*(p,g,\psi,\varrho,\beta,\phi,\gamma,\zeta)$ are obtained. Also, distortion theorem, growth theorem and coefficient inequalities are established.


2021 ◽  
Vol 54 (1) ◽  
pp. 37-46
Author(s):  
Muhammad Ghaffar Khan ◽  
Bakhtiar Ahmad ◽  
Raees Khan ◽  
Muhammad Zubair ◽  
Zabidin Salleh

Abstract The main objective of the present paper is to define a class of q q -starlike functions with respect to symmetric points in circular domain. Some interesting results of these functions have been evaluated in this article. The sufficiency criteria in the form of convolutions are evaluated. Furthermore, other geometric properties such as coefficient bounds, distortion theorem, closure theorem and extreme point theorem are also obtained for these newly defined functions.


2021 ◽  
Vol 8 (1) ◽  
pp. 66-76
Author(s):  
B. Venkateswarlu ◽  
P. Thirupathi Reddy ◽  
R. Madhuri Shilpa ◽  
G. Swapna

Abstract In this paper,we introduce and study a new subclass of meromorphic functions associated with a certain differential operator on Hilbert space. For this class, we obtain several properties like the coefficient inequality, growth and distortion theorem, radius of close-to-convexity, starlikeness and meromorphically convexity and integral transforms. Further, it is shown that this class is closed under convex linear combinations.


2020 ◽  
Vol 31 (4) ◽  
pp. 80
Author(s):  
Teba Rzaij Al-Kubaisi ◽  
AbdulRahman Salman Juma

The main object of the present paper is to introduce the class of meromorphic univalent function K* (σ,τ,S) defined by differential operator with study some geometric properties like coefficient inequality , growth theorem and distortion theorem, radii of starlikeness and convexity of f(z) in the class K* (σ,τ,S) .Also the concept of convolution (Hadamard product) investigate and Neighborhoods of the elements of class K* (σ,τ,S) are obtained.


2020 ◽  
Vol 102 (4) ◽  
Author(s):  
Tatsuto Murayama ◽  
Asaki Saito ◽  
Peter Davis

2020 ◽  
pp. 2350-2360
Author(s):  
Osamah N. Kassar ◽  
Abdul Rahman S. Juma

In this paper, making use of the q-R uscheweyh differential  operator , and  the  notion of t h e J anowski f unction, we study some subclasses of  holomorphic   f- unction s . Moreover , we obtain so me geometric characterization like co efficient es timat es , rad ii of starlikeness ,distortion theorem , close- t o- convexity , con vexity, ext reme point s, neighborhoods, and the i nte gral mean inequalities of func tions affiliation to these c lasses


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