ON ARGUMENT PROPERTY OF CERTAIN ANALYTIC FUNCTIONS

被引:0
作者
Nunokawa, Mamoru [1 ]
Bah, Alpha Mamadou [2 ]
机构
[1] Univ Gunma, Dept Math, Maebashi, Gunma 371, Japan
[2] Hiroshima Univ, Grad Sch Engn, Dept Appl Math, Hiroshima 7398527, Japan
来源
STUDIA UNIVERSITATIS BABES-BOLYAI MATHEMATICA | 2010年 / 55卷 / 03期
关键词
Univalent functions; Argument property of analytic functions;
D O I
暂无
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
In this paper we generalize the results of Libera and McGregor concerning argument property of analytic functions. We use the result in [3] to prove the following: Theorem. Let f(z) = z vertical bar Sigma(infinity)(n=p+K) a(n)z(n), g(z) = z vertical bar Sigma(infinity)(n=p+K) b(n)z(n) be analytic in Delta, f(z) not equal 0 in 0 < vertical bar z vertical bar < 1, and suppose that for some alpha, beta (0 < alpha < 1, 0 < beta < 1) vertical bar arg (f'(z)/g'(z)vertical bar < pi/2 alpha + Tan(-1) 2 alpha beta/1-beta(2) - Tan(-1) 2 alpha beta/(1-beta(2))root 1+alpha(2) in Delta, and taht g'(z)/zg(z) (sic) 1+beta z/1-beta z where (sic) means subordination. Then we have vertical bar arg(f(z)/g(z)vertical bar < pi/2 alpha in Delta.
引用
收藏
页码:163 / 168
页数:6
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