Radius problems in the class S L*

被引:75
作者
Sokol, Janusz [1 ]
机构
[1] Rzeszow Univ Technol, Dept Math, PL-35959 Rzeszow, Poland
关键词
Analytic functions; Convex functions; Starlike functions; k-Starlike functions; alpha-Starlike functions; alpha-Convex functions; Strongly starlike functions; S L*-functions; Radius of starlikeness; Radius of convexity;
D O I
10.1016/j.amc.2009.04.031
中图分类号
O29 [应用数学];
学科分类号
070104 ;
摘要
Let S L* denote the class of all analytic functions f in the unit disc u with the normalization f(0) = f'(0) - 1 = 0 and satisfying the condition vertical bar[zf'(z)/f(z)](2) -1 vertical bar < 1; z is an element of u, thuszf'(z)/f(z) is in the interior of the right half of the lemniscate of Bernoulli (x(2) + y(2))(2)-(x(2) - y(2)) = 0. The relations between S L* and others classes geometrically defined are considered. The radii of alpha-convexity, of alpha-starlikeness (and some of others) of integral is an element of S L* are determined. (c) 2009 Elsevier Inc. All rights reserved.
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页码:569 / 573
页数:5
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