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1.
欧氏空间R~(n+1)中满足方程H=-X~N+λ的浸入超曲面称为λ超曲面.本文主要研究欧氏空间中完备λ超曲面的第二拼挤问题.设M为R~(n+1)中具有多项式体积增长的n维完备λ超曲面.设M的第二基本形式为A.本文证明存在正的绝对常数γ,如果|λ|≤γ,β_λ≤|A|~2≤β_λ+~1/21,其中β_λ=1/2(2+λ~2+|λ|(λ~2+4)~1/2),那么|A|~2≡β_λ,λ≥0,且M必为n维球面S~n(n~1/2)、n维圆柱面S~k(k~1/2)×R~(n-k)(1≤ k≤ n-1)或S(((λ2+4)~1/2-|λ|)/2)×R~(n-1)之一.  相似文献   

2.
高维空间的一个Heilbronn型问题   总被引:2,自引:2,他引:2  
洪毅  汪国强  陶志穗 《数学学报》1997,40(1):144-153
本文研究了以下Heilbronn型问题:设S是欧氏空间按R~k 中由有限个点A_1,A_2,…,A_n组成的集合,令d(S)=min{A_iA_j|1≤i相似文献   

3.
李伟平  赵峰 《数学学报》2017,60(5):815-822
设λ_f/(n)是全模群Γ上权为k的全纯Hecke特征形f的第n个Fourier系数,Λ(n)是Mangoldt函数.本文得到了如下估计∑_(Xn≤2X)Λ(n)λ_f(n)e(n~(1/2)α)■f,αX~(5/6)(logX)~(13/2),(α0),改进了Zhao的结果。  相似文献   

4.
Edrei和Fuchs建立了如下定理 定理A 设f(z)是级为λ的亚纯函数,0<λ<1。令u=1-δ(0,f),v=1-δ(∞,f),0≤u,v≤1。这里δ(α,f)代表Nevanlinna亏量,则u~2 v~2-2uvcosπλ≥sin~2πλ。且u相似文献   

5.
设g(ζ)=ζ+sum from n=0 to ∞b_nζ~(-n)为α级亚纯星形函数(0≤α<1,|ζ|>1),函数ψ(z)=z+sum from n=2 to ∞α_nZ~n为单位园内的凸单叶函数。本文得到,若α∈(1/2,1),则g(ζ)※ζ~2ψ(1/ζ)(|ζ|>1)为α级亚纯星形函数,作为这个结果的一个推论,文[4]中的猜测在α∈(1/2,1)内成立。  相似文献   

6.
Ⅰ.引言 1.1932年L.Ahlfors证明了下述结果: 定理A.设Z平面上的λ级亚纯函数f(z)的反函数具有k个判别直接超越奇点,则当λ<1时有0≤k≤1;当λ≥1时有k≤2λ。  相似文献   

7.
定理1 如果x~2+y~2≤R~2,S=mx+ny,m、n为常数且mn≠0,那么,当且仅当这圆与这动直线相切时,S才取得最值:S_max=RM~2+n~2~(1/2)S_min=-RM~2+n~2~(1/2)。证明设圆心(0,0)到直线的距离为d,那么d=|S|/(m~2+n~2)~2(1/m~2+n~2)≤R ∴-R(m~2+n~2)~2(1/m~2+n~2)≤S≤R(m~2+n~2)~2(1/m~2+n~2)当且仅当圆与直线相切时,  相似文献   

8.
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.  相似文献   

9.
改进了Ozawa的一个关于整函数的唯一性定理,得到了∞为亏值的亚纯函数唯一性的相应的几个结论.设亚纯函数f(z)与g(z)的级(或者下级)为有穷的非整数,满足.f=0→g=0,f=1g=1,f=∞9=∞,若∞为f(z)的Borel例外值,则f≡g.以及设f(z)与g(z)为C中非常数的亚纯函数,它们的级λ为有穷且非整数,再设它们满足f=0→g=0,f=1g=1,f=∞g=∞,若δ(∞,f)=1,f(z)为正规增长函数,则f≡g.  相似文献   

10.
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.  相似文献   

11.
12.
张丽娜  吴建华 《数学进展》2008,37(1):115-117
One of the most fundamental problems in theoretical biology is to explain the mechanisms by which patterns and forms are created in the'living world. In his seminal paper "The Chemical Basis of Morphogenesis", Turing showed that a system of coupled reaction-diffusion equations can be used to describe patterns and forms in biological systems. However, the first experimental evidence to the Turing patterns was observed by De Kepper and her associates(1990) on the CIMA reaction in an open unstirred reactor, almost 40 years after Turing's prediction. Lengyel and Epstein characterized this famous experiment using a system of reaction-diffusion equations. The Lengyel-Epstein model is in the form as follows  相似文献   

13.
In this paper, we study the explicit representation and convergence of (0, 1; 0)-interpolation on infinite interval, which means to determine a polynomial of degree ≤ 3n - 2 when the function values are prescribed at two set of points namely the zeros of Hn(x) and H′n(x) and the first derivatives at the zeros of H′n(x).  相似文献   

14.
As early as in 1990, Professor Sun Yongsheng, suggested his students at Beijing Normal University to consider research problems on the unit sphere. Under his guidance and encouragement his students started the research on spherical harmonic analysis and approximation. In this paper, we incompletely introduce the main achievements in this area obtained by our group and relative researchers during recent 5 years (2001-2005). The main topics are: convergence of Cesaro summability, a.e. and strong summability of Fourier-Laplace series; smoothness and K-functionals; Kolmogorov and linear widths.  相似文献   

15.
We study a class of self-similar processes with stationary increments belonging to higher order Wiener chaoses which are similar to Hermite processes. We obtain an almost sure wavelet-like expansion of these processes. This allows us to compute the pointwise and local Hölder regularity of sample paths and to analyse their behaviour at infinity. We also provide some results on the Hausdorff dimension of the range and graphs of multidimensional anisotropic self-similar processes with stationary increments defined by multiple Wiener–Itô integrals.  相似文献   

16.
Schr(o)dinger operator is a central subject in the mathematical study of quantum mechanics.Consider the Schrodinger operator H = -△ V on R, where △ = d2/dx2 and the potential function V is real valued. In Fourier analysis, it is well-known that a square integrable function admits an expansion with exponentials as eigenfunctions of -△. A natural conjecture is that an L2 function admits a similar expansion in terms of "eigenfunctions" of H, a perturbation of the Laplacian (see [7], Ch. Ⅺ and the notes), under certain condition on V.  相似文献   

17.
It is considered the class of Riemann surfaces with dimT1 = 0, where T1 is a subclass of exact harmonic forms which is one of the factors in the orthogonal decomposition of the spaceΩH of harmonic forms of the surface, namely The surfaces in the class OHD and the class of planar surfaces satisfy dimT1 = 0. A.Pfluger posed the question whether there might exist other surfaces outside those two classes. Here it is shown that in the case of finite genus g, we should look for a surface S with dimT1 = 0 among the surfaces of the form Sg\K , where Sg is a closed surface of genus g and K a compact set of positive harmonic measure with perfect components and very irregular boundary.  相似文献   

18.
正Guest Editors:Hong Chen,Shanghai Jiao Tong University,Shanghai,China Guohua Wan,Shanghai Jiao Tong University,Shanghai,China David Yao,Columbia University,New York,USA Scope:Healthcare delivery worldwide has been fraught with high cost,low efficiency and poor quality of patient care service.For the field of operations research(OR),healthcare offers some of the biggest challenges as well as best opportunities in  相似文献   

19.
20.
Due to the resolution of current laser technology, the accuracy of corneal topography as measured by the videokeratoscope is no longer adequate to provide precise enough data for refractive surgery or for the fitting of customized contact lenses. We present an algorithm for recovering corneal topography that makes use of modern differential geometric techniques and numerical descent in Sobolev spaces. We believe this algorithm may be used with the photo- and videokeratoscope to increase the accuracy of the recovered corneal topography.  相似文献   

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