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一类近于凸函数子族的研究
引用本文:蔡振锋.一类近于凸函数子族的研究[J].湖北大学学报(自然科学版),2011,33(3):330-335.
作者姓名:蔡振锋
作者单位:湖北工业大学理学院,湖北武汉,430068
摘    要:函数g(z)〈G(z),当且仅当存在单位开圆盘E内的解析函数w(z)∈B0,即满足:w(0)=0,|w(z)|〈1,使得g(z)=G(w(z))(z∈E),设PA,B]={p(z):p(0)=1,p(z)在E内解析且满足p(z)〈1+Az/1+Bz,-1≤B〈A≤1,一个函数g(z)∈CA,B]当且仅当(zg'(z))'/g'(z)〈1+Az/1+Az.函数族KB'A,B]={f(z):f(0)=f'(0)-1=0,f(z)在E内解析g(z)∈CA,B],且Re{zf'(z)/g(z)}〉B,-1≤B〈A≤1},这是近于凸函数的一个子集,从而这些函数是单叶的.利用Janowski介绍的函数类PA,B]的性质,参考Khalida Inayat Noor研究CB+A,B]的方法,研究这个函数族系数估计和半径问题,同时讨论KB’A,B]与其他单叶函数子族的关系.

关 键 词:解析函数  近于凸函数  偏差定理  系数估计  凸半径

A subclass of close-to-convex functions
CAI Zhenfeng.A subclass of close-to-convex functions[J].Journal of Hubei University(Natural Science Edition),2011,33(3):330-335.
Authors:CAI Zhenfeng
Institution:CAI Zhenfeng (School of Science, Hubei University of Technology, Wuhan 430068, China)
Abstract:A function g(z)〈G(z) if and only if it exited is a w(z)∈B0, where w(0)=0,|w(z)|〈1 , so that g(z)=G(w(z))(z∈E).Let PA,B], -1≤B〈A≤1, denoted the class of functions p(z) : p(0)=1, analytic in the unit open disk E, such that p(z) was subordinate to 1+Az/1+Bz.A function g(z)was said to belong to the class CA,B]if and only if (zg'(z))'/g'(z) was in PA, B], KBA, B]-the class of analytic functions f(z),where f(0)=f'(0)-1=0, regular in E satisfying the condition. Re {zf'(z)/g(z)}〉B, g∈CA,B], -1≤B〈A≤1.These functions in this class were close-to-convex and hence univalent. With the help of the new Class P-A,B]which introduced by Janowski, we studied its relationship with other functions. Co-efficient problem, distortion theorems, radius of convexity and other properties were solved.
Keywords:analytic function  close-to-convex function  distortion theorems  coefficient estimate  radius of convexity
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