涉及分担值的一个正规定则

A Normality Criterion of Meromorphic Functions Related to Sharing a Value

主要得到了以下结果：设是一族平面区域D内的亚纯函数,a,b为有穷非零复数,k为大于1的整数.如果对于F中的任一元素f,满足f-a的零点重数至少为k,f（z）=a f（k）（z）=a,f（k）（z）=b f（k＋1）（z）=b,则当k≥3时,F为正规族,k=2并且a/b≠4时,F为正规族.并且给出了1个例子说明条件a/b≠4是必要的.

This paper mainly obtains the following result：let F be a family of meromorphic functions on a domain D in the complex plane,a,b be finite non-zero complex numbers such that f-a has only zeros multiplicity at least k for each f in F.If for each f in F,f（z）=a f（k）（z）=a,f（k）（z）=b f（k＋1）（z）=b,then for k≥3,F is normal in D and for k=2 and a/b≠4,F is normal in D.An example is given to illustrate the condition of a/b≠4 is necessary.