scholarly journals On a subclass of analytic functions defined by Ruscheweyh operator

2012 ◽  
Vol 21 (1) ◽  
pp. 49-56
Author(s):  
ABDUL RAHMAN SALMAN JUMA ◽  
◽  
LUMINITA-IOANA COTIRLA ◽  
Keyword(s):  
Analytic Function ◽  
Analytic Functions ◽  
Unit Disc ◽  
Inclusion Relation ◽  
Distortion Bounds ◽  
Ruscheweyh Derivative ◽  
Coefficient Condition ◽  
Necessary And Sufficient

By using the Ruscheweyh derivative, we have introduced a subclass of analytic functions with negative coefficients in the unit disc. Some properties of analytic function as necessary and sufficient coefficient condition for this class are provided. Distortion bounds, inclusion relation and various properties are also determined.

scholarly journals Class of Analytic Function Related with Uniformly Convex and Janowski’s Functions

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Akhter Rasheed ◽  
Saqib Hussain ◽  
Muhammad Asad Zaighum ◽  
Maslina Darus
Keyword(s):  
Analytic Function ◽  
Analytic Functions ◽  
Unit Disc ◽  
Extreme Points ◽  
Distortion Theorem ◽  
Open Unit ◽  
Uniformly Convex ◽  
Coefficient Estimates ◽  
Open Unit Disc

In this paper, we introduce a new subclass of analytic functions in open unit disc. We obtain coefficient estimates, extreme points, and distortion theorem. We also derived the radii of close-to-convexity and starlikeness for this class.

scholarly journals On Some Properties of Cowen-Douglas Class of Operators

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Parastoo Heiatian Naeini ◽  
Bahmann Yousefi
Keyword(s):  
Hilbert Space ◽  
Analytic Function ◽  
Essential Spectrum ◽  
Analytic Functions ◽  
Sufficient Conditions ◽  
Multiplication Operator ◽  
Multiplication Operators ◽  
Space Of Analytic Functions ◽  
Class Operator ◽  
Necessary And Sufficient

We will consider multiplication operators on a Hilbert space of analytic functions on a domainΩ⊂C. For a bounded analytic functionφonΩ, we will give necessary and sufficient conditions under which the complement of the essential spectrum ofMφinφΩbecomes nonempty and this gives conditions for the adjoint of the multiplication operatorMφbelongs to the Cowen-Douglas class of operators. Also, we characterize the structure of the essential spectrum of a multiplication operator and we determine the commutants of certain multiplication operators. Finally, we investigate the reflexivity of a Cowen-Douglas class operator.

scholarly journals Applications of Mittag-Leffer Type Poisson Distribution to a Subclass of Analytic Functions Involving Conic-Type Regions

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Muhammad Ghaffar Khan ◽  
Bakhtiar Ahmad ◽  
Nazar Khan ◽  
Wali Khan Mashwani ◽  
Sama Arjika ◽  
...  
Keyword(s):  
Poisson Distribution ◽  
Analytic Functions ◽  
Convex Combination ◽  
Partial Sums ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Geometric Properties ◽  
Distortion Bounds ◽  
Janowski Functions ◽  
Necessary And Sufficient

In this article, we introduce a new subclass of analytic functions utilizing the idea of Mittag-Leffler type Poisson distribution associated with the Janowski functions. Further, we discuss some important geometric properties like necessary and sufficient condition, convex combination, growth and distortion bounds, Fekete-Szegö inequality, and partial sums for this newly defined class.

scholarly journals A CONVOLUTION APPROACH TO CERTAIN SUBCLASSES OF STARLIKE FUNCTIONS

1992 ◽  
Vol 23 (4) ◽  
pp. 311-320
Author(s):  
T . RAM REDDY ◽  
O. P. JUNEJA ◽  
K. SATHYANARAYANA
Keyword(s):  
Analytic Function ◽  
Analytic Functions ◽  
Unit Disc ◽  
Starlike Functions ◽  
Integral Transforms ◽  
Open Unit ◽  
Sufficient Condition ◽  
Open Unit Disc ◽  
Containment Property ◽  
Convolution Approach

The class $R_\gamma(A,B)$ for $-1\le B < A\le 1$ and $\gamma> (A- 1)/(1- B)$ consisting of normalised analytic functions in the open unit disc is defined with the help of Convolution technique. It consists of univalent starlike functions for $\gamma\ge 0$. We establish containment property, integral transforms and a sufficient condition for an analytic function to be in $R\gamma(A,B)$. Using the concept of dual spaces we find a convolution condition for a function in this class.

scholarly journals A Subclass of Harmonic Univalent Functions Associated with -Analogue of Dziok-Srivastava Operator

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Huda Aldweby ◽  
Maslina Darus
Keyword(s):  
Hypergeometric Function ◽  
Univalent Functions ◽  
Extreme Points ◽  
Distortion Bounds ◽  
Basic Hypergeometric Function ◽  
Generalized Operator ◽  
Coefficient Condition ◽  
Necessary And Sufficient ◽  
Complex Valued

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.

scholarly journals a*-families of analytic functions

1984 ◽  
Vol 7 (3) ◽  
pp. 435-442 ◽  
Author(s):  
G. P. Kapoor ◽  
A. K. Mishra
Keyword(s):  
Analytic Function ◽  
Taylor Series ◽  
Analytic Functions ◽  
Extreme Points ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
New Family ◽  
Symmetric Points ◽  
Necessary And Sufficient

Using convolutions, a new family of analytic functions is introduced. This family, calleda*-family, serves in certain situations to unify the study of many previously well known classes of analytic functions like multivalent convex, starlike, close-to-convex or prestarlike functions, functions starlike with respect to symmetric points and other such classes related to the class of univalent or multivalent functions. A necessary and sufficient condition on the Taylor series coefficients so that an analytic function with negative coefficients is in ana*-family is obtained and sharp coefficents bound for functions in such a family is deduced. The extreme points of ana*-family of functions with negative coefficients are completely determined. Finally, it is shown that Zmorvic conjecture is true if the concerned families consist of functions with negative coefficients.

scholarly journals Characterisations for analytic functions of bounded mean oscillation

1992 ◽  
Vol 46 (1) ◽  
pp. 115-125 ◽  
Author(s):  
Jie Miao
Keyword(s):  
Analytic Function ◽  
Fractional Derivative ◽  
Lebesgue Measure ◽  
Analytic Functions ◽  
Unit Disc ◽  
Carleson Measure ◽  
Bounded Mean Oscillation ◽  
Mean Oscillation ◽  
Significant Extension

Let α > 0 and let f[α](z) be the αth fractional derivative of an analytic function f on the unit disc D. In this paper we show that f ∈ BMOA if and only if |f[α](z)|2 (l - |z|2)2α−1dA(z) is a Carleson measure and f ∈ VMOA if and only if |f[α](z)|2 (1 − |z|2)2α−1dA(z) is a vanishing Carleson measure, where A denotes the normalised Lebesgue measure on D. Hence a significant extension of familiar characterisations for analytic functions of bounded and vanishing mean oscillation is obtained.

scholarly journals On a certain subclass of analytic functions defined by a generalized S˘al˘agean operator and Ruscheweyh derivative

2012 ◽  
Vol 28 (2) ◽  
pp. 183-190
Author(s):  
ALINA ALB LUPAS ◽  
Keyword(s):  
Analytic Functions ◽  
Unit Disc ◽  
Differential Subordination ◽  
Open Unit ◽  
Open Unit Disc ◽  
Ruscheweyh Derivative ◽  
Differential Subordinations

In the present paper we define a new operator using the generalized Sal˘ agean and Ruscheweyh operators. Denote by ˘ RDm λ,α the operator given by RDm λ,α : An → An, RDm λ,αf(z) = (1 − α)Rmf(z) + αDm λ f(z), z ∈ U, where Rmf(z) denote the Ruscheweyh derivative, Dm λ f(z) is the generalized Sal˘ agean operator and ˘ An = {f ∈ H(U) : f(z) = z +an+1z n+1 +. . . , z ∈ U} is the class of normalized analytic functions. A certain subclass, denoted by RDm (δ, λ, α) , of analytic functions in the open unit disc is introduced by means of the new operator. By making use of the concept of differential subordination we will derive various properties and characteristics of the class RDm (δ, λ, α) . Also, several differential subordinations are established regarding the operator RDm λ,α.

scholarly journals A New Class of Analytic Functions Associated with Sălăgean Operator

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Muhammad Arif ◽  
Khurshid Ahmad ◽  
Jin-Lin Liu ◽  
Janusz Sokół
Keyword(s):  
Linear Operator ◽  
Analytic Functions ◽  
Coefficient Estimates ◽  
Inclusion Relation ◽  
New Class ◽  
Sălăgean Operator ◽  
Salagean Operator ◽  
Distortion Bounds

The main object of the present paper is to investigate a number of useful properties such as inclusion relation, distortion bounds, coefficient estimates, and subordination results for a new subclass of analytic functions which are defined here by means of a linear operator. Several known consequences of the results are also pointed out.

Geometric Proofs of some Classical Results on Boundary Values for Analytic Functions

1994 ◽  
Vol 37 (2) ◽  
pp. 263-269 ◽  
Author(s):  
Enrique Villamor
Keyword(s):  
Analytic Function ◽  
Analytic Functions ◽  
Unit Disc ◽  
Logarithmic Capacity ◽  
Geometric Proof ◽  
Boundary Values ◽  
Dirichlet Integral ◽  
Capacity Zero ◽  
Extremal Metric ◽  
Nontangential Limits

AbstractIn this note we are going to give a geometric proof, using the method of the extremal metric, of the following result of Beurling. For any analytic function f(z) in the unit disc Δ of the plane with a bounded Dirichlet integral, the set E on the boundary of the unit disc where the nontangential limits of f(z) do not exist has logarithmic capacity zero. Also, using an unpublished result of Beurling, we will prove different results on boundary values for different classes of functions.

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