THE FEKETE-SZEG PROBLEM FOR CLOSE-TO-CONVEX FUNCTIONS WITH RESPECT TO THE KOEBE FUNCTION

An analytic function f in the unit disk D ：= {z ∈ C ： ｜z｜ 〈 1}, standardly normalized, is called close-to-convex with respect to the Koebe function k（z） ：= z/（1-z）2, z ∈ D, if there exists δ ∈ （-π/2,π/2） such that Re {eiδ（1-z）2f′（z）} 〉 0, z ∈ D. For the class C（k） of all close-to-convex functions with respect to k, related to the class of functions convex in the positive direction of the imaginary axis, the Fekete-Szego problem is studied.

On Sufficient Conditions for p-valently Close-to-convexity

Let A p(n)(p, n∈N=｛1,2,…｝) denote the class of functions of the form f(z)=z p+a p+n z p+n +… which are analytic in the unit disc E=｛z:｜z｜<1｝. By using the method of differential subordinati ons we give some sufficient conditions for a function f(z)∈A p(n) to be a certain subclass R p(n,k) of p-valently close-to-convexity funct ions.

Fekete-Szego problem for close-to-convex functions with respect to a certain convex function dependent on a real parameter

Given α∈[0, 1], let hα（z） ：= z/（1 - αz）, z ∈ D ：= {z ∈ C： ｜z｜ 〈 1}. An analytic standardly normalized function f in D is called close-to-convex with respect to hα if there exists δ ∈ （-π/2, π/2） such that Re{e^iδ zf′（z）/hα（z）} 〉 0, z ∈ D. For the class l（hα） of all close-to-convex functions with respect to hα, the Fekete-Szego problem is studied.

Applications of the Differential Operator to the Class of p-Valent Functions

In this paper, we define some new subclasses of strongly close-to-star and strongly close-to-convex p-valent functions defined in the open unit disc by using a differential operator. Some inclusion results, convolution properties are studied.

Some Inequalities on <i>p</i>-Valent Functions Related to Geometric Structure Based on <i>q</i>-Derivative

By applying the q-derivative, we introduce two new subclasses of p-valent functions with positive coefficients. By means of the well-known Jack’s lemma, some inequalities related to starlike, convex and close-to-convex functions are also obtained.

A REMARK ON CERTAIN DIFFERENTIAL INEQUALITIES INVOLVING p-VALENT FUNCTIONS

In the present paper, we study certain differential inequalities involving p-valent functions and obtain sufficient conditions for uniformly p-valent starlikeness and uniformly p-valent convexity. We also offer a correct version of some known criteria for uniformly p-valent starlike and uniformly p-valent convex functions.

On a Class of Analytic Functions Defined by Ruscheweyh Derivatives

In the present paper a class of extended close-to-convex functions Qk,λ(α,β,ρ) defined by making use of Ruscheweyh derivatives is introduced and studied. We provide integral representations, distortion theorem, radius of close-to-convexity and Hadamard product properties for this class.