scholarly journals Characterizations for certain subclasses of starlike and convex functions associated with Bessel functions

Filomat ◽  
2016 ◽  
Vol 30 (7) ◽  
pp. 1911-1917 ◽  
Author(s):  
Nak Cho ◽  
Hyo Lee ◽  
Rekha Srivastava

In the present paper, we obtain some characterizations for a certain generalized Bessel function of the first kind to be in the subclasses SpT(?,?), UCT(?,?), PT(?) and CPT(?) of normalized analytic functions in the open unit disk U. Furthermore, we consider an integral operator related to the generalized Bessel Function which we have characterized here.

2016 ◽  
Vol 32 (1) ◽  
pp. 123-129
Author(s):  
VIRGIL PESCAR ◽  
◽  
CONSTANTIN LUCIAN ALDEA ◽  
◽  

In this paper we consider an integral operator for analytic functions in the open unit disk and we derive the order of convexity for this integral operator, on certain classes of univalent functions.


Author(s):  
Young Jae Sim ◽  
Oh Sang Kwon

For real numbersαandβsuch that0≤α<1<β, we denote by𝒦α,βthe class of normalized analytic functions which satisfy the following two sided-inequality:α<ℜ1+zf′′z/f′z<β  z∈𝕌,where𝕌denotes the open unit disk. We find some relationships involving functions in the class𝒦(α,β). And we estimate the bounds of coefficients and solve the Fekete-Szegö problem for functions in this class. Furthermore, we investigate the bounds of initial coefficients of inverse functions or biunivalent functions.


2014 ◽  
Vol 2014 ◽  
pp. 1-4
Author(s):  
Edmond Aliaga ◽  
Nikola Tuneski

The class𝒰(λ,μ)of normalized analytic functions that satisfy|(z/f(z))1+μ·f′(z)−1|<λfor allzin the open unit disk is studied and sufficient conditions for anα-convex function to be in𝒰(λ,μ)are given.


2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Roberta Bucur ◽  
Loriana Andrei ◽  
Daniel Breaz

We obtain sufficient conditions for the univalence, starlikeness, and convexity of a new integral operator defined on the space of normalized analytic functions in the open unit disk. Some subordination results for the new integral operator are also given. Several corollaries follow as special cases.


Filomat ◽  
2017 ◽  
Vol 31 (2) ◽  
pp. 227-245 ◽  
Author(s):  
Najla Alarifi ◽  
Rosihan Ali ◽  
V. Ravichandran

Let f be a normalized analytic function in the open unit disk of the complex plane satisfying zf'(z)/f(z) is subordinate to a given analytic function ?. A sharp bound is obtained for the second Hankel determinant of the kth-root transform z[f(zk)/zk]1/k. Best bounds for the Hankel determinant are also derived for the kth-root transform of several other classes, which include the class of ?-convex functions and ?-logarithmically convex functions. These bounds are expressed in terms of the coefficients of the given function ?, and thus connect with earlier known results for particular choices of ?.


2015 ◽  
Vol 23 (1) ◽  
pp. 213-224
Author(s):  
Adriana Oprea ◽  
Daniel Breaz

AbstractFor analytic functions in the open unit disk U, we define a new general integral operator. The main object of the this paper is to study this new integral operator and to determine univalence conditions of it. Several corollaries of the main results are also considered.


2021 ◽  
Vol 66 (2) ◽  
pp. 339-351
Author(s):  
Barbatu Camelia ◽  
Daniel Breaz

"In this paper we introduce a new general integral operator for analytic functions in the open unit disk U and we obtain su cient conditions for univalence of this integral operator."


2020 ◽  
Vol 28 (2) ◽  
pp. 33-47
Author(s):  
Camelia Bărbatu ◽  
Daniel Breaz

AbstractFor some classes of analytic functions f, g, h and k in the open unit disk 𝕌, we consider the general integral operator 𝒢n, that was introduced in a recent work [1] and we obtain new conditions of univalence for this integral operator. The key tools in the proofs of our results are the Pascu’s and the Pescar’s univalence criteria, as well as the Mocanu’s and Şerb’s Lemma. Some corollaries of the main results are also considered. Relevant connections of the results presented here with various other known results are briefly indicated.


2012 ◽  
Vol 62 (1) ◽  
Author(s):  
Jin-Lin Liu

AbstractFor analytic functions f(z) in the open unit disk U and convex functions g(z) in U, Nunokawa et al. [NUNOKAWA, M.—OWA, S.—NISHIWAKI, J.—KUROKI, K.—HAYAMI, T: Differential subordination and argumental property, Comput. Math. Appl. 56 (2008), 2733–2736] have proved one theorem which is a generalization of the result [POMMERENKE, CH.: On close-toconvex analytic functions, Trans. Amer. Math. Soc. 114 (1965), 176–186]. The object of the present paper is to generalize the theorem due to Nunokawa et al..


Filomat ◽  
2020 ◽  
Vol 34 (7) ◽  
pp. 2225-2234
Author(s):  
Camelia Bǎrbatu ◽  
Daniel Breaz

For some classes of analytic functions f and 1 in the open unit disk U, we consider the general integral operatorMn, that was introduced in a recent work [2] and we obtain new conditions of univalence for this integral operator. The key tools in the proofs of our results are the Pascu?s and the Pescar?s univalence criteria. Some corollaries of the main results are also considered. Relevant connections of the results presented here with various other known results are briefly indicated.


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