共查询到20条相似文献,搜索用时 15 毫秒
1.
By using the Nevanlinna theory, we prove some normality criteria for a family of meromorphic functions under a condition on differential polynomials generated by the members of the family. 相似文献
2.
Let k be a positive integer and F be a family of meromorphic functions in a domain D⊂C such that each f∈F has only zeros of multiplicity at least k+1. If for each pair (f, g) in F, ff(k) and gg(k) share a non-zero complex number a ignoring multiplicity, then F is normal in D. 相似文献
3.
Pei-Chu Hu 《Journal of Mathematical Analysis and Applications》2009,357(2):323-731
Take positive integers n,k?2. Let F be a family of meromorphic functions in a domain D⊂C such that each f∈F has only zeros of multiplicity at least k. If, for each pair (f,g) in F, fn(f(k)) and gn(g(k)) share a non-zero complex number a ignoring multiplicity, then F is normal in D. 相似文献
4.
5.
LetF be families of meromorphic functions in a domainD, and letR be a rational function whose degree is at least 3. If, for anyf∈
F, the composite functionR(f) has no fixed-point inD, thenF is normal inD. The number 3 is best possible. A new and much simplified proof of a result of Pang and Zalcman concerning normality and,
shared values is also given. 相似文献
6.
The purpose of this paper is to investigate the normal families and shared sets of meromorphic functions. The results obtained
complement the related results due to Fang, Liu and Pang. 相似文献
7.
Normality and quasinormality of zero-free meromorphic functions 总被引:1,自引:0,他引:1
Jian Ming Chang 《数学学报(英文版)》2012,28(4):707-716
Let k, K ∈ N and F be a family of zero-free meromorphic functions in a domain D such that for each f ∈ F , f(k)-1 has at most K zeros, ignoring multiplicity. Then F is quasinormal of order at most ν = K k+1 , where ν is equal to the largest integer not exceeding K/k+1 . In particular, if K = k, then F is normal. The results are sharp. 相似文献
8.
The main purpose of the present paper is to derive some new criteria for meromorphic multivalent starlike functions. 相似文献
9.
Lipei Liu 《Journal of Mathematical Analysis and Applications》2007,331(1):177-183
In this paper, we study the normality of a family of meromorphic functions and obtain some normality results for meromorphic functions, which improve and generalize the related results of Gu, Bergweiler and Lin. 相似文献
10.
Wei Chen Pei‐Chu Hu Hong‐Gen Tian 《Mathematical Methods in the Applied Sciences》2016,39(5):1176-1182
T. Qian In this paper, we prove two theorems on normal families of meromorphic functions, which improve a few of results from several authors. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
11.
On normal families of meromorphic functions 总被引:1,自引:0,他引:1
12.
Jianming Chang 《Archiv der Mathematik》2010,94(6):555-564
Let k be a positive integer and let ${\mathcal F}Let k be a positive integer and let F{\mathcal F} be a family of functions meromorphic in a plane domain D, all of whose zeros have multiplicity at least k + 3. If there exists a subset E of D which has no accumulation points in D such that for each function f ? F{f\in\mathcal F}, f
(k)(z) − 1 has no zeros in D\E{D\setminus E}, then F{\mathcal F} is normal. The number k + 3 is sharp. The proof uses complex dynamics. 相似文献
13.
P. Niu Y. Xu 《Journal of Contemporary Mathematical Analysis (Armenian Academy of Sciences)》2016,51(3):160-165
The paper is devoted to the normal families of meromorphic functions and shared functions. Generalizing a result of Chang (2013), we prove the following theorem. Let h (≠≡ 0,∞) be a meromorphic function on a domain D and let k be a positive integer. Let F be a family of meromorphic functions on D, all of whose zeros have multiplicity at least k + 2, such that for each pair of functions f and g from F, f and g share the value 0, and f(k) and g(k) share the function h. If for every f ∈ F, at each common zero of f and h the multiplicities mf for f and mh for h satisfy mf ≥ mh + k + 1 for k > 1 and mf ≥ 2mh + 3 for k = 1, and at each common pole of f and h, the multiplicities nf for f and nh for h satisfy nf ≥ nh + 1, then the family F is normal on D. 相似文献
14.
Let k be a positive integer, let M be a positive number, let F be a family of meromorphic functions in a domain D, all of whose zeros are of multiplicity at least k, and let h be a holomorphic function in D, h ≢ 0. If, for every f ∈ F, f and f
(k) share 0, and |f(z)| ≥ M whenever f
(k)(z) = h(z), then F is normal in D. The condition that f and f
(k) share 0 cannot be weakened, and the condition that |f(z)| ≥ M whenever f
(k)(z) = h(z) cannot be replaced by the condition that |f(z)| ≥ 0 whenever f
(k)(z) = h(z). This improves some results due to Fang and Zalcman [2] etc. 相似文献
15.
In this paper, we study the normality of families of meromorphic functions. We prove the result: Let α(z) be a holomorphic function and \({\mathcal{F}}\) a family of meromorphic functions in a domain D, P(z) be a polynomial of degree at least 3. If P ○ f(z) and P ○ g(z) share α(z) IM for each pair \({f(z),g(z)\in \mathcal{F}}\) and one of the following conditions holds: (1) P(z) ? α(z 0) has at least three distinct zeros for any \({z_{0}\in D}\); (2) There exists \({z_{0}\in D}\) such that P(z) ? α(z 0) has at most two distinct zeros and α(z) is nonconstant. Assume that β 0 is a zero of P(z) ? α(z 0) with multiplicity p and that the multiplicities l and k of zeros of f(z) ? β 0 and α(z) ? α(z 0) at z 0, respectively, satisfy k ≠ lp, for all \({f(z)\in\mathcal{F}}\). Then \({\mathcal{F}}\) is normal in D. In particular, the result is a kind of generalization of the famous Montel criterion. 相似文献
16.
本文研究了亚纯函数族涉及复合有理函数与分担亚纯函数的正规性. 证明了一个正规定则:设 α(z) 和 F 分别是区域 D 上的亚纯函数与亚纯函数族, R(z) 是一个次数不低于 3 的有理函数.如果对族 F 中函数 f(z) 和 g(z), R○f(z) 和 R○g(z) 分担 α(z) IM,并且下述 条件之一成立:
(1) 对任何 z0 ∈ D, R(z)-α(z0) 有至少三个不同的零点或极点;
(2) 存在 z0 ∈ D 使得 R(z)-α(z0):=(z-β0)pH(z) 至多有两个零点(或极点) β0,同时 k ≠ l|p|,其中 l 和 k 分别是 f(z)-β0 和 α(z)-α(z0) 在 z0 处的零点重数, H(z) 是满足 H(β0) ≠ 0, ∞ 的有理函数, α(z) 非常数并满足 α(z0) ∈ C ∪{∞}.
那么 F 在 D 内正规.特别地,这个结果是著名的 Montel 正规定则的一种推广. 相似文献
(1) 对任何 z0 ∈ D, R(z)-α(z0) 有至少三个不同的零点或极点;
(2) 存在 z0 ∈ D 使得 R(z)-α(z0):=(z-β0)pH(z) 至多有两个零点(或极点) β0,同时 k ≠ l|p|,其中 l 和 k 分别是 f(z)-β0 和 α(z)-α(z0) 在 z0 处的零点重数, H(z) 是满足 H(β0) ≠ 0, ∞ 的有理函数, α(z) 非常数并满足 α(z0) ∈ C ∪{∞}.
那么 F 在 D 内正规.特别地,这个结果是著名的 Montel 正规定则的一种推广. 相似文献
17.
Xiaojun Huang 《Journal of Mathematical Analysis and Applications》2003,277(1):190-198
In this paper, we study the normality of a family of meromorphic functions and general criteria for normality of families of meromorphic functions with multiple zeros concerning shared values are obtained. 相似文献
18.
Z. Pavicevic 《Moscow University Mathematics Bulletin》2011,66(4):171-172
The paper contains two parts. In the first part, the behavior of meromorphic functions along arbitrary Jordan curves ending at a single boundary point is studied. The second part describes applications of the results of the first part to the study of the value distribution of meromorphic functions in terms of P-sequences. 相似文献
19.
20.
Qian Lu 《Journal of Mathematical Analysis and Applications》2008,340(1):394-400
We consider the normality criterion for a families F meromorphic in the unit disc Δ, and show that if there exist functions a(z) holomorphic in Δ, a(z)≠1, for each z∈Δ, such that there not only exists a positive number ε0 such that |an(a(z)−1)−1|?ε0 for arbitrary sequence of integers an(n∈N) and for any z∈Δ, but also exists a positive number B>0 such that for every f(z)∈F, B|f′(z)|?|f(z)| whenever f(z)f″(z)−a(z)(f′2(z))=0 in Δ. Then is normal in Δ. 相似文献