Some properties for certain classes of univalent functions defined by differential inequalities

Let A be the space of functions analytic in the unit disk D = {z:|z| 1}.Let U denote the set of all functions f ∈ A satisfying the conditions f(0) = f'(0)-1 = 0 and|f'(z)(z/f(z))~2-1|1(|z|1).Also,let Ω denote the set of all functions f ∈ A satisfying the conditions f(0) = f'(0)-1 = 0and|zf'(z)-f(z)|1/2(|z|1).In this article,we discuss the properties of U and Ω.     

Some radii problems related to certain p-valent meromorphic functions

The purpose of the present paper is to introduce several new classes of p-valent meromorphic functions defined by Ruscheweyh derivative operator for meromorphic multivalent functions. Further, we investigate the radii problems of these analytic classes in the punctured unit disk.     

On certain classes of analytic functions defined by Noor integral operator

Integral operator, introduced by Noor, is defined by using convolution. Let f_n(z)=z/(1−z)ⁿ⁺¹, n∈N₀, and let f be analytic in the unit disc E. Then I_nf=f⁽⁻¹⁾_n★f, where f_n★f⁽⁻¹⁾_n=z/(1−z). Using this operator, certain classes of analytic functions, related with the classes of functions with bounded boundary rotation and bounded boundary radius rotation, are defined and studied in detail. Some basic properties, rate of growth of coefficients, and a radius problem are investigated. It is shown that these classes are closed under convolution with convex functions. Most of the results are best possible in some sense.     

Majorization for certain classes of analytic functions defined by fractional derivatives

Here we investigate a majorization problem involving starlike function of complex order belonging to a certain class defined by means of fractional derivatives. Relevant connections of the main results obtained in this paper with those given by earlier workers on the subject are also pointed out.     

On integral operators for certain classes of p-valent functions associated with generalized multiplier transformations

In this paper, we study new generalized integral operators for the classes of p-valent functions associated with generalized multiplier transformations.     

Subordination and superordination properties of p-valent functions defined by a generalized fractional differintegral operator

For a generalized fractional differintegral operator associated with p- valent functions, we study different properties of differential subordination and superordination related to this operator.     

Optimal quadrature problem on classes defined by kernels satisfying certain oscillation properties

We consider some classes of 2π-periodic functions defined by a class of operators having certain oscillation properties, which include the classical Sobolev class and a class of analytic functions which can not be represented as a convolution class as its special cases. Let be the largest integer not bigger than x. We prove that on these classes of functions the rectangular formula

Convolution properties for certain classes of multivalent functions

Recently N.E. Cho, O.S. Kwon and H.M. Srivastava [Nak Eun Cho, Oh Sang Kwon, H.M. Srivastava, Inclusion relationships and argument properties for certain subclasses of multivalent functions associated with a family of linear operators, J. Math. Anal. Appl. 292 (2004) 470-483] have introduced the class of multivalent analytic functions and have given a number of results. This class has been defined by means of a special linear operator associated with the Gaussian hypergeometric function. In this paper we have extended some of the previous results and have given other properties of this class. We have made use of differential subordinations and properties of convolution in geometric function theory.     

Some constructive properties of functions defined on the sphere

The norm of difference operators for functions defined on the sphere is investigated. A mistake in Rustamov's results is pointed out by a counterexample. And correct result is given. Results of convergence in norm of difference operators acting on the differentiable functions on the sphere are obtained. The highest possible degree tending to zero for the moduli of continuity of fractional order for non-constant valued functions are discussed. The work is supported by NSF of China, Grant No. 19771009.     

Some constructive properties of functions defined on the sphere

The norm of difference operators for functions defined on the sphere is investigated. A mistake in Rustamov's results is pointed out by a counterexample. And correct result is given. Results of convergence in norm of difference operators acting on the differentiable functions on the sphere are obtained. The highest possible degree tending to zero for the moduli of continuity of fractional order for non-constant valued functions are discussed.     

Some properties of certain meromorphic close-to-convex functions

In the present paper, we introduce and investigate a certain subclass of meromorphic close-to-convex functions. Such results as coefficient inequalities, convolution property, distortion property and radius of meromorphic convexity are derived.     

Subordination properties for a certain class of analytic functions defined by the Salagean operator

In this paper we derive several subordination results for a certain class of analytic functions defined by the Salagean operator.     

Some applications of Miller-Mocanu lemma on certain classes of meromorphic functions

In this paper, making use of a linear operator we introduce and study certain new classes of meromorphic functions. We derive some inclusion results. These classes contain many known classes as a special case.