English

A normality Criterion for a Family of Meromorphic Functions

Complex Variables 2024-02-20 v1

Abstract

Schwick, in [6], states that let F\mathcal{F} be a family of meromorphic functions on a domain DD and if for each fFf\in\mathcal{F}, (fn)(k)1(f^n)^{(k)}\neq 1, for zDz\in D, where n,kn, k are positive integers such that nk+3n\geq k+3, then F\mathcal{F} is a normal family in DD. In this paper, we investigate the opposite view that if for each fFf\in\mathcal{F}, (fn)(k)(z)ψ(z)(f^n)^{(k)}(z)-\psi(z) has zeros in DD, where ψ(z)\psi(z) is a holomorphic function in DD, then what can be said about the normality of the family F\mathcal{F}?

Keywords

Cite

@article{arxiv.1909.00139,
  title  = {A normality Criterion for a Family of Meromorphic Functions},
  author = {Gopal Datt and Sanjay Kumar},
  journal= {arXiv preprint arXiv:1909.00139},
  year   = {2024}
}