SOME NORMAL CRITERIA FOR FAMILIES OF MEROMORPHIC FUNCTIONS

Abstract

In the paper, we study the normality of families of meromorphicfunctions related a Hayman Conjecture. We consider whether afamily meromorphic functions $\mathcal{F}$ is normal in $D$, iffor each function $f$ in $\mathcal{F}$, $f' + af^n =b$ has at most one zero, where $n$ is a positive integer, $a$ and $b\neq 0$ are two finite complex numbers. Some examples show that the conditions in our results are best possible.