On the number of zeros of certain rational harmonic functions

被引:57
作者
Khavinson, D [1 ]
Neumann, G
机构
[1] Univ Arkansas, Dept Math Sci, Fayetteville, AR 72701 USA
[2] Kansas State Univ, Dept Math, Manhattan, KS 66506 USA
关键词
Argument principle; Fixed points; Gravitational lenses; Rational harmonic mappings;
D O I
10.1090/S0002-9939-05-08058-5
中图分类号
O29 [应用数学];
学科分类号
070104 ;
摘要
Extending a result of Khavinson and Swiatek (2003) we show that the rational harmonic function <(r(z))over bar > - z, where r(z) is a rational function of degree n > 1, has no more than 5n - 5 complex zeros. Applications to gravitational lensing are discussed. In particular, this result settles a conjecture by Rhie concerning the maximum number of lensed images due to an n-point gravitational lens.
引用
收藏
页码:1077 / 1085
页数:9
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