scholarly journals On the univalency for certain subclass of analytic functions involving Ruscheweyh derivatives

2002 ◽  
Vol 31 (9) ◽  
pp. 567-575 ◽  
Author(s):  
Liu Mingsheng
Keyword(s):  
Unit Disk ◽  
Analytic Functions ◽  
Covering Theorem ◽  
Inclusion Relations ◽  
Special Case ◽  
Class Of Functions

LetHbe the class of functionsf(z)of the formf(z)=z+∑ K=2 + ∞a k z k, which are analytic in the unit diskU={z;|z|<1}. In this paper, we introduce a new subclassBλ(μ,α,ρ)ofHand study its inclusion relations, the condition of univalency, and covering theorem. The results obtained include the related results of some authors as their special case. We also get some new results.

scholarly journals Convolution properties of a class of bounded analytic functions

1992 ◽  
Vol 45 (1) ◽  
pp. 9-23 ◽  
Author(s):  
Zou Zhongzhu ◽  
Shigeyoshi Owa
Keyword(s):  
Integral Operator ◽  
Unit Disk ◽  
Analytic Functions ◽  
Bounded Analytic Functions ◽  
Class A ◽  
Convolution Properties ◽  
Class Of Functions

Let A be the class of functions f(z) which are analytic in the unit disk U with f(0) = f′(0) - 1 = 0. A subclass S(λ, M) (λ > 0, M > 0) of A is introduced. The object of the present paper is to prove some interesting convolution properties of functions f(z) belonging to the class S(λ, M). Also a certain integral operator J for f(z) in the class A is considered.

scholarly journals A note on neighborhoods of analytic functions having positive real part

1990 ◽  
Vol 13 (3) ◽  
pp. 425-429 ◽  
Author(s):  
Janice B. Walker
Keyword(s):  
Unit Disk ◽  
Analytic Functions ◽  
Positive Real Part ◽  
Positive Real ◽  
Class Of Functions

LetPdenote the set of all functions analytic in the unit diskD={z||z|<1}having the formp(z)=1+∑k=1∞pkzkwithRe{p(z)}>0. Forδ≥0, letNδ(p)be those functionsq(z)=1+∑k=1∞qkzkanalytic inDwith∑k=1∞|pk−qk|≤δ. We denote byP′the class of functions analytic inDhaving the formp(z)=1+∑k=1∞pkzkwithRe{[zp(z)]′}>0. We show thatP′is a subclass ofPand detemineδso thatNδ(p)⊂Pforp∈P′.

scholarly journals A Note on the Class of Functions with Bounded Turning

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Rabha W. Ibrahim ◽  
Adem Kılıçman
Keyword(s):  
Unit Disk ◽  
Upper Bound ◽  
Analytic Functions ◽  
Geometric Representation ◽  
Jack’S Lemma ◽  
Bounded Turning ◽  
Class Of Functions ◽  
Jack's Lemma

We consider subclasses of functions with bounded turning for normalized analytic functions in the unit disk. The geometric representation is introduced, some subordination relations are suggested, and the upper bound of the pre-Schwarzian norm for these functions is computed. Moreover, by employing Jack's lemma, we obtain a convex class in the class of functions of bounded turning and relations with other classes are posed.

scholarly journals On Coefficient Functionals for Functions with Coefficients Bounded by 1

Mathematics ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 491
Author(s):  
Paweł Zaprawa ◽  
Anna Futa ◽  
Magdalena Jastrzębska
Keyword(s):  
Unit Disk ◽  
Upper Bound ◽  
Analytic Functions ◽  
Positive Real Part ◽  
Extremal Functions ◽  
Hankel Determinant ◽  
Schwarz Function ◽  
Positive Real ◽  
Special Case

In this paper, we discuss two well-known coefficient functionals a 2 a 4 - a 3 2 and a 4 - a 2 a 3 . The first one is called the Hankel determinant of order 2. The second one is a special case of Zalcman functional. We consider them for functions in the class Q R ( 1 2 ) of analytic functions with real coefficients which satisfy the condition ( ) f ( z ) z > 1 2 for z in the unit disk Δ . It is known that all coefficients of f ∈ Q R ( 1 2 ) are bounded by 1. We find the upper bound of a 2 a 4 - a 3 2 and the bound of | a 4 - a 2 a 3 | . We also consider a few subclasses of Q R ( 1 2 ) and we estimate the above mentioned functionals. In our research two different methods are applied. The first method connects the coefficients of a function in a given class with coefficients of a corresponding Schwarz function or a function with positive real part. The second method is based on the theorem of formulated by Szapiel. According to this theorem, we can point out the extremal functions in this problem, that is, functions for which equalities in the estimates hold. The obtained estimates significantly extend the results previously established for the discussed classes. They allow to compare the behavior of the coefficient functionals considered in the case of real coefficients and arbitrary coefficients.

scholarly journals Some properties of multivalent analytic functions associated with an integral operator

2013 ◽  
Vol 21 (1) ◽  
pp. 277-284
Author(s):  
Yi-Hui Xu ◽  
Cai-Mei Yan
Keyword(s):  
Integral Operator ◽  
Unit Disk ◽  
Analytic Functions ◽  
Open Unit ◽  
Open Unit Disk ◽  
Class Of Functions

Abstract Let A(p) denote the class of functions of the form f(z) = zp Σ∞k=1+p akzk (p ∈ N = {1, 2, 3,...}) which are analytic in the open unit disk U = {z : z ∈ C and |z| < 1} By making use of the Noor integral operator, we obtain some interesting properties of multivalent analytic functions.

scholarly journals A Generalized Class of Functions Defined by the q-Difference Operator

Symmetry ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2361
Author(s):  
Loriana Andrei ◽  
Vasile-Aurel Caus
Keyword(s):  
Analytic Function ◽  
Unit Disk ◽  
Analytic Functions ◽  
Difference Operator ◽  
Sufficient Conditions ◽  
Open Unit ◽  
Open Unit Disk ◽  
New Class ◽  
The Relationship ◽  
Class Of Functions

The goal of the present investigation is to introduce a new class of analytic functions (Kt,q), defined in the open unit disk, by means of the q-difference operator, which may have symmetric or assymetric properties, and to establish the relationship between the new defined class and appropriate subordination. We derived relationships of this class and obtained sufficient conditions for an analytic function to be Kt,q. Finally, in the concluding section, we have taken the decision to restate the clearly-proved fact that any attempt to create the rather simple (p,q)-variations of the results, which we have provided in this paper, will be a rather inconsequential and trivial work, simply because the added parameter p is obviously redundant.

scholarly journals Certain subclasses of Spiral-like univalent functions related with Pascal distribution series

2021 ◽  
Vol 7 (2) ◽  
pp. 312-323
Author(s):  
Gangadharan Murugusundaramoorthy
Keyword(s):  
Integral Operator ◽  
Unit Disk ◽  
Analytic Functions ◽  
Univalent Functions ◽  
Sufficient Conditions ◽  
Open Unit ◽  
Open Unit Disk ◽  
Inclusion Relations ◽  
Pascal Distribution

Abstract The purpose of the present paper is to find the sufficient conditions for the subclasses of analytic functions associated with Pascal distribution to be in subclasses of spiral-like univalent functions and inclusion relations for such subclasses in the open unit disk 𝔻. Further, we consider the properties of integral operator related to Pascal distribution series. Several corollaries and consequences of the main results are also considered.

scholarly journals On the Fekete-Szegö Problem for a Class of Analytic Functions

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
Zhigang Peng
Keyword(s):  
Power Series ◽  
Real Number ◽  
Unit Disk ◽  
Convex Functions ◽  
Analytic Functions ◽  
Upper Bounds ◽  
The Family ◽  
Class Of Functions

Let 𝒜 denote the class of functions which are analytic in the unit disk D={z:|z|<1} and given by the power series f(z)=z+∑n=2∞‍anzn. Let C be the class of convex functions. In this paper, we give the upper bounds of |a3-μa22| for all real number μ and for any f(z) in the family 𝒱={f(z):f∈𝒜, Re(f(z)/g(z))>0 for  some g∈C}.

scholarly journals Fractional Calculus of Analytic Functions Concerned with Möbius Transformations

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
Nicoleta Breaz ◽  
Daniel Breaz ◽  
Shigeyoshi Owa
Keyword(s):  
Fractional Calculus ◽  
Unit Disk ◽  
Analytic Functions ◽  
Fractional Derivatives ◽  
Fractional Integrals ◽  
Open Unit ◽  
Open Unit Disk ◽  
Möbius Transformations ◽  
Class Of Functions ◽  
Mobius Transformations

LetAbe the class of functionsf(z)in the open unit diskUwithf(0)=0andf′(0)=1. Also, letw(ζ)be a Möbius transformation inUfor somez∈U. Applying the Möbius transformations, we consider some properties of fractional calculus (fractional derivatives and fractional integrals) off(z)∈A. Also, some interesting examples for fractional calculus are given.

scholarly journals On a class of analytic functions governed by subordination

2019 ◽  
Vol 11 (1) ◽  
pp. 144-155 ◽  
Author(s):  
Ravinder Krishna Raina ◽  
Janusz Sokół
Keyword(s):  
Unit Disk ◽  
Analytic Functions ◽  
Open Unit ◽  
Open Unit Disk ◽  
Basic Properties ◽  
Radius Of Convexity ◽  
Class Of Functions

Abstract The purpose of this paper is to introduce a class of functions ℱλ, λ ∈ [0, 1], consisting of analytic functions f normalized by f(0) = f´(0) − 1 = 0 in the open unit disk U which satisfies the subordination condition that $${\rm{z}}f'\left( {\rm{z}} \right)/\left\{ {\left( {1 - \lambda } \right){\rm{f}}\left( {\rm{z}} \right) + \lambda {\rm{z}}} \right\} \prec {\rm{q}}\left( {\rm{z}} \right),\,\,\,\,\,{\rm{z}} \in {\rm{\mathbb{U},}}$$ where ${\rm{q}}\left( {\rm{z}} \right) = \sqrt {1 + {{\rm{z}}^{\rm{2}}}} + {\rm{z}}$ . Some basic properties (including the radius of convexity) are obtained for this class of functions.

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