Notes on normal families of meromorphic functions sharing a set with their derivatives

摘要

We study the normality of families of meromorphic functions sharing a set consisting of two or three distinct finite values to improve and extend Theorem 1 in Liu-Pang cite{15} and Theorem 1.1 in Liu-Chang cite{16}. Examples are provided to show that the results in this paper, in a sense, are the best possible.