整函数及其差分分担有限集的唯一性

研究了整函数及其差分多项式分担有限复数集的唯一性,得到了如下结果:设S_m={1,ω,…,ω~(m-1)},其中ω=cos(2π/m)+i sin(2π/m),c为非零有限复数,n(>5),m(≥2)均为正整数.如果f(z),g(z)为有限级整函数,满足E(S_m,f(z)~n(f(z)-1)f(z+c))=E(S_m,g(z)~n(g(z)-1))g(z+c)),那么f(z)≡g(z).     

关于Fermat型微分差分方程的亚纯解

本文研究了Fermat型微分及微分-差分方程亚纯解的存在性问题,证明了如果m,n为正整数,则不存在非常数亚纯函数f(z)满足微分方程f′(z)~m+f(z)~n=1,但m=2,n=3或4和m=1,n=2除外.文中给出例子表明例外情况的方程亚纯解的存在性,并讨论该微分方程整函数解.同时,探讨了复微分-差分方程f′(z)~m+f(z+c)~n=1非常数亚纯解的存在性.     

整函数及其差分的唯一性

设f是一个有穷级的超越整函数,a,b,c是3个有穷复数,满足c≠0,a≠b,且n为正整数.如果a是f的Borel例外值,且Δ_c~nf(z)与f(z)IM分担b,则f(z)=a+Ae~(Bz),其中A,B为两个非零常数.     

涉及导数与差分的亚纯函数唯一性

设f,g是两个非常数亚纯函数,a是一个非零有穷复数,n≥5是一个正整数.若[f(z)]~n与[g(z)]~n CM分担a,f(z)与g(z) CM分担∞,且N_(1))(r,f)=S(r,f),则或者f(z)三tg(z),其中t~n=1;或者f(z)g(z)≡t,其中t~n=a~2.由此改进了涉及导数与差分的一些亚纯函数唯一性的结果.     

涉及整函数差分算子的唯一性定理

作者研究了关于有穷级整函数两个差分算子的分担值问题,证明了:令f(z)是满足λ(f-a(z))＜p(f)的有穷级超越整函数,其中a(z)(∈ S(f))是整函数且满足p(a(z))＜1,并令η(∈C)是常数且满足Δ2ηf(z)≠0.如果Δ2ηf(z)和Δηf(z)CM分担Δηa(z),其中Δηa(z)∈S(Δ2ηf(z...     

亚纯函数及其差分的唯一性

本文证明了:对具有两个Borel例外值a(∈C)和b(∈C∪{∞})的有限级超越亚纯函数,如果f(z+η)-f(z)和f(z)CM分担a,b,其中η(∈C)满足f(z+η)■f(z),那么b=∞,a=0且f(z)=ce~(c_1z),其中c,c_1为非零常数.     

亚纯函数涉及分担函数的正规定则

本文研究亚纯函数涉及分担函数的正规性.设■为定义在区域D上的全纯函数族,n,k,m(≥0)是三个整数,其中n≥k+m+2,p(z)是区域D上零点重数为m的全纯函数.如果函数族■中任意两个函数(f,g)均满足(f~n)~((k))和(g~n)~((k))分担p(z),则■在D上正规.     

基于Salagean算子的bi-单叶函数系数估计

讨论和研究了受限于Salagean算子且同时满足:1+1/b((D~(n+1)f(z)/(D~nf(z)))-1)φ(z)和1+1/b((D~(n+1)f~(-1)(ω)/(D~nf~(-1)(ω))-1)Ψ(ω)的bi-单叶解析函数的系数估计问题,这里φ(z)和Ψ(ω)为正实部函数.主要的研究结果直接推广了先前相应工作.     

一类分担有理函数的亚纯函数的唯一性

利用复分析的值分布理论研究了亚纯函数的唯一性,给出了下面的结果.设q(z)为k次有理函数,f(z)和g(z)是两个超越亚纯函数,fg与q没有共同的极点.n是正整数且n≥max{11,k+1}.如果f~n(z)f′(z),g~n(z)g′(z)分担有理函数q(z)CM,则f(z)=c_1e~(c∫q(z)dz),g(z)=c_2e~(-c∫q(z)dz),这里c_1,c_2和c是三个常数且满足(c_1c_2)~(n+1)c~2=-1;或者f(z)≡tg(z),其中t是一个常数满足t~(n+1)=1.     

涉及差分算子的亚纯函数的唯一性

本文研究涉及差分算子的亚纯函数的唯一性问题,得到一个唯一性定理:设f是一个级不小于2的有限级整函数,η是非零复数,a(z)是不恒等于0的整函数,满足ρ(a)ρ(f)和λ(f-a)ρ(f).若f-a与Δnηf-a(n=1或2)CM分担0,则f(z)是整数级的,且ρ(a)=1或ρ(a)≥ρ(f)-1,f(z)=a(z)+[Δnηa(z)-a(z)]eA(z),其中A(z)是一个次数和ρ(f)相等的多项式.     

一类非线性复微分差分方程解的不存在性

该文研究了一类复微分差分方程[f(z)f'(z)]n + fm(z + r) = 1,[f(z)f'(z)]n + [f(z + r)-f(z)]m = 1,[f(z) f'(z)] 2 + P2(z) f2(z + η) = Q(z)eα(z) 的超越整函数解,其中P(z), Q(z)为非零多项式,α(z)为多项式,...     

一族特殊的星像函數

<正> 設函數w=f(z)在單位圓|z|<1中是正則的.f(0)=0,f′(0)=1.假如f(z)是單葉的,那末w=f(z)映照|z|<1於w平面上的單葉的像D_f.記這種單葉函數的全體為S.若D_f以原點w=0為星形中心,就稱f(z)是|z|<1中的星     

Universal sums of three quadratic polynomials

Let a,b,c,d,e and f be integers with a≥ c≥ e> 0,b>-a and b≡a(mod 2),d>-c and d≡c(mod 2),f>-e and f≡e(mod 2).Suppose that b≥d if a=c,and d≥f if c=e.When b(a-b),d(c-d) and f(e-f) are not all zero,we prove that if each n∈N={0,1,2,...} can be written as x(ax+b)/2+y(cy+d)/2+z(ez+f)/2 with x,y,z∈N then the tuple(a,b,c,d,e,f) must be on our list of 473 candidates,and show that 56 of them meet our purpose.When b∈[0,a),d∈[0,c) and f∈[0,e),we investigate the universal tuples(a,b,c,d,e,f) over Z for which any n∈N can be written as x(ax+b)/2+y(cy+d)/2+z(ez+f)/2 with x,y,z∈Z,and show that there are totally 12,082 such candidates some of which are proved to be universal tuples over Z.For example,we show that any n∈N can be written as x(x+1)/2+y(3y+1)/2+z(5z+1)/2 with x,y,z∈Z,and conjecture that each n∈N can be written as x(x+1)/2+y(3y+1)/2+z(5z+1)/2 with x,y,z∈N.     

Convex Holes Produce Lower Bounds for Coefficients

Let D denote the open unit disk and $ f:D \to \bar {{\bf C}}$ be meromorphic and injective in D . Especially, we consider such f which have an expansion $$ f(z) = z + \sum \limits_{n=2}^{\infty }a_n(\;f\,)z^n $$ in a neighbourhood of the origin and map D onto a domain whose complement with respect to $\bar {{\bf C}}$ is convex. Let the set of these functions be denoted by Co . We fix | f m 1 ( X )| for f ] Co and determine the inner and outer radius of the ring domain which is the domain of variability of a 2 ( f ) for such f . Further, it is shown that f ] Co implies that $$ \phi (z) = z+2 {f'(z) \over f''(z)}$$ is holomorphic in D and maps D into itself. This implication in turn implies the inequalities | a n ( f )| S 1 for f ] Co and n = 2,3,4. In addition, we show that | a n ( f )| S 1/2 for f ] Co and all n S 2 .     

The convergence of padé approximants and the size of the power series coefficients

Let f be a power series ∑a_izⁱ with complex coefficients. The (n. n) Pade approximant to f is a rational function P/Q where P and Q are polynomials, Q(z) ? 0, of degree ≦ n such that f(z)Q(z)-P(z) = Az²ⁿ⁺¹ + higher degree terms. It is proved that if the coefficients a_i satisfy a certain growth condition, then a corresponding subsequence of the sequence of (n, n) Pade approximants converges to f in the region where the power series f converges, except on an exceptional set E having a certain Hausdorff measure 0. It is also proved that the result is best possible in the sense that we may have divergence on E. In particular,there exists an entire function f such that the sequence of (ny n) Pade approximants diverges everywhere (except at 0)     

On Ω-limit Sets of Discrete-time Dynamical Systems

The paper investigates z -limit sets for discrete-time dynamical systems of the form x n +1 = f n +1 ( x n ), n S 0, with each f n mapping an interval I of R into itself. For autonomous systems, i.e. f n = f for all n , and f continuous on I =[ a , b ], the case that all z -limit sets consist of one point only is characterized by several equivalent conditions, one being that f has no 2-periodic points. The non-autonomous case assumes that the functions f n converge uniformly to a continuous function f X that has no 2-periodic points. It is shown that the z -limit sets are closed intervals consisting of fixed points of f X only. Under certain conditions these closed intervals contain exactly one point each. This allows a treatment of certain discrete-time dynamical systems in R n .     

开拓劳宾生和戈鲁辛的几个定理

<正> 1.设 p 次对称函数(?)在单位圆|z|<1中是正则的单叶的,此种函数的全体成一函数族 S_p.当p=1时,简讯 S_1为 S.设ω=f(z)∈S_p 映照|z|<1于 W 面上时,其像关于原点成星形,此种 f(z)成 S_p 之一子族S_p.设 f(z)∈S_p,     

A NOTE TO THE NEVANJUNNA''S FUNDAMENTAL THEOREM

In this paper, the author extends Nevanlinna's second fundamental theorem and establishes the following inequality: Let $\[p(s,u) = {A_v}(s){u^v} + {A_1}(s){u^{v - 1}} + \cdots + {A_0}(s)\]$ be an irreducible two-variable polynomial and $f(s)$ a transcendental entire function, then $$\[(\nu - 1)T(r,f) < N(r,\frac{1}{{p(z,f(z))}}) + S(r,f)\]$$ with $$\[S(r,f) = O(\log (rT(r,f)))n.e\]$$ where an. "n.e" means that the estimation holds for all large r with possibly an exceptional of finite measure when f is of infinite order.