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In this article we prove some normality criteria for a family of meromorphic functions which involves sharing of a non-zero value by certain differential monomials generated by the members of the family. These results generalizes some of…

Complex Variables · Mathematics 2024-02-20 Gopal Datt , Sanjay Kumar

We consider the family of all meromorphic functions $f$ of the form $$ f(z)=\frac{1}{z}+b_0+b_1z+b_2z^2+\cdots $$ analytic and locally univalent in the puncture disk $\mathbb{D}_0:=\{z\in\mathbb{C}:\,0<|z|<1\}$. Our first objective in this…

Complex Variables · Mathematics 2017-09-05 Vibhuti Arora , Swadesh Kumar Sahoo

For two meromorphic functions $ f $ and $ g $, the equation $ f^m+g^m=1 $ can be regarded as Fermat-type equations. Using Nevanlinna theory for meromorphic functions in several complex variables, the main purpose of this paper is to…

Complex Variables · Mathematics 2022-01-26 Goutam Haldar

A theorem of A. Ostrowski describing meromorphic functions f such that the family {f(kz):k in C*} is normal, is generalized to holomorphic maps from $C*$ to a projective space.

Complex Variables · Mathematics 2013-12-23 Alexandre Eremenko

In this paper we prove some normality criteria for a family of meromorphic functions concerning shared analytic functions, which extend or generalized some result obtained by Y. F. Wang, M. L. Fang~\cite{WF} and J. Qui, T. Zhu ~\cite{QZ}.

Complex Variables · Mathematics 2019-06-10 Sanjay Kumar , Poonam Rani

In this paper, a normality criterion concerning a sequence of meromorphic functions and their differential polynomials is obtained. Precisely, we have proved: Let $\left\{f_j\right\}$ be a sequence of meromorphic functions in the open unit…

Complex Variables · Mathematics 2024-06-14 Nikhil Bharti

Peter Lappan in [9] proved that for each $n\in \mathbb{N}=\{1,2,3,\dots\}$, let $f_{1,n}, f_{2,n}$ and $f_{3,n}$ be three continuous functions on $\mathbb{D}:=\{z\in \mathbb{C} : |z| < 1\}$ such that for each $j=1,2,3,$ the sequence…

Complex Variables · Mathematics 2026-05-13 Gopal Datt , Kushal Lalwani , Ashish Kumar Trivedi

We consider the class $\Sigma(p)$ of univalent meromorphic functions $f$ on $\ID$ having simple pole at $z=p\in[0,1)$ with residue 1. Let $\Sigma_k(p)$ be the class of functions in $\Sigma(p)$ which have $k$-quasiconformal extension to the…

Complex Variables · Mathematics 2017-05-11 Bappaditya Bhowmik , Goutam Satpati

In this paper, we study the class ${\Sigma^{(m)}(p)}$ of meromorphic univalent functions $f$ in $\mathbb{D}$ with a pole of order ${m \geq 1}$ at $p \in (0,1)$, admitting a $k$-quasiconformal extension ($0 \leq k < 1$) to…

Complex Variables · Mathematics 2025-11-13 Molla Basir Ahamed , Partha Pratim Roy

Let $(M,g)$ be a compact manifold and let $-\Delta \phi_k = \lambda_k \phi_k$ be the sequence of Laplacian eigenfunctions. We present a curious new phenomenon which, so far, we only managed to understand in a few highly specialized cases:…

Spectral Theory · Mathematics 2017-06-06 Xiuyuan Cheng , Gal Mishne , Stefan Steinerberger

We establish a criterion for local boundedness and hence normality of a family $\F$ of analytic functions on a domain $D$ in the complex plane whose corresponding family of derivatives is locally bounded. Furthermore we investigate the…

Dynamical Systems · Mathematics 2013-03-01 Dinesh Kumar , Sanjay Kumar

In this paper we first introduced a domain called generalized Dirichlet fundamental domain $\mathcal{F}^{*}$ for a Fuchsian group $G$ whose generators contain parabolic elements. This allows us to show that a quasisymmetric homeomorphism…

Complex Variables · Mathematics 2022-06-09 Shengjin Huo , Mengzhen Zhao

Beardon and Minda gave a characterization of normal families of holomorphic and meromorphic functions in terms of a locally uniform Lipschitz condition. Here, we generalize this viewpoint to families of mappings in higher dimensions that…

Complex Variables · Mathematics 2022-01-25 Alastair N. Fletcher , Daniel A. Nicks

A semigroup (dynamical system) generated by $C^{1+\alpha}$-contracting mappings is considered. We call a such semigroup regular if the maximum $K$ of the conformal dilatations of generators, the maximum $l$ of the norms of the derivatives…

Dynamical Systems · Mathematics 2016-09-06 Yunping Jiang

In this paper we define a new concept of quasi-convolution for analytic functions normalized by $f(0)=0$ and $f^\prime(0)=1$ in the unit disk $E=\{z\in \mathbb{C}\colon |z|<1\}$. We apply this new approach to study the closure properties of…

Complex Variables · Mathematics 2010-04-16 K. O. Babalola

In this paper we prove the result: Let $\mathcal{F}$ be a family of meromorphic functions on a domain $\Omega$ such that every pair of members of $\mathcal{F}$ shares a set $S:=\left\{\psi_1(z), \psi_2(z), \psi_3(z) \right\}$ in $\Omega$,…

Complex Variables · Mathematics 2015-09-22 Kuldeep Singh Charak , Virender Singh

In this paper we prove some normality criteria for a family of meromorphic functions, which involves the zeros of certain differential polynomials generated by the members of the family.

Complex Variables · Mathematics 2017-04-19 Sanjay Kumar , Poonam Rani

Let $f$ be an orientation preserving homeomorphisms on the circle with several break points, that is, its derivative $Df$ has jump discontinuities at these points. We study Rauzy-Veech renormalizations of piecewise smooth circle…

Dynamical Systems · Mathematics 2018-07-30 Kleyber Cunha , Akhtam Dzhalilov , Abdumajid Begmatov

We study renormalizations of piecewise smooth homeomorphisms on the circle, by considering such maps as generalized interval exchange maps of genus one. Suppose that $Df$ is absolutely continuous on each interval of continuity and…

Dynamical Systems · Mathematics 2019-03-20 Abdumajid Begmatov , Kleyber Cunha

The main aim of this article is to give some sufficient conditions for a family of meromorphic mappings on a domain D in C^n into P^N(C) to be meromorphically normal if they satisfy only some very weak conditions with respect to moving…

Complex Variables · Mathematics 2015-05-11 Gerd Dethloff , Thai Do Duc , Trang Pham Nguyen Thu