## Some results on value distribution of meromorphic functions.(English)Zbl 1085.30030

Several theorems on normality criteria for meromorphic functions and families of meromorphic functions are proved using value distribution theory. As an example on obtained results the following theorem is stated: Let $$\mathcal F$$ be a family of meromorphic functions on the unit disc $$\Delta$$. Let $$a$$ be a finite non-zero complex number and let $$k$$ be a positive integer. If for every function $$f\in\mathcal F$$, $$f$$ has no zeros and $$ff^{(k)}\neq a$$, then $$\mathcal F$$ is normal on $$\Delta$$.

### MSC:

 30D35 Value distribution of meromorphic functions of one complex variable, Nevanlinna theory 30D45 Normal functions of one complex variable, normal families

### Keywords:

meromorphic functions; normal family
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