A note on normality of meromorphic functions

被引:2
|
作者
Chang, Jianming [1 ]
机构
[1] Inst Technol, Dept Math, Changshu 215500, Jiangsu, Peoples R China
关键词
holomorphic functions; meromorphic functions; normal family;
D O I
10.3792/pjaa.83.60
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
Let F be a family of all functions f meromorphic in a domain D C C, for which, all zeros have multiplicity at least k, and f(Z) = 0 double left right arrow f((k))(Z) = 1 double right arrow vertical bar f((k+1))(Z)vertical bar <= h, where k is an element of N and h is an element of R+ are given. Examples show that T is not normal in general (at least for k = 1 or k = 2). The example we give for k = 1 shows that a recent result of Y. Xu [5] is not correct. However, we prove that for k not equal 2, there exists a positive integer K is an element of N such that the subfamily 9 = {f is an element of F : all possible poles of f in D have multiplicity at least K} of T is normal. This generalizes our result in [1]. The case k = 2 is also considered.
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页码:60 / 62
页数:3
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