Normality criteria for families of zero-free meromorphic functions

Abstract

AbstractIn this paper, we prove some normality criteria for families of zero-free meromorphic functions. The results of this paper are generalizations of some problems studied by Chang [Acta Math. Sin. (Engl. Ser.) 28 (2012), 707–716] and Dethloff–Tan–Thin [J. Math. Anal. Appl. 411 (2014), 675–683].