首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 906 毫秒
1.
△^2u=λu+N+4/N—4+μf(x)的多解存在性   总被引:1,自引:1,他引:0  
讨论了非齐次双调和方程边值问题{△^2u=λu+N+4/uN-4+uf(x),x∈Ωn=△u|n=0,的两个正解的存在性和非存在性,这里Ω是R^N内有界光滑区域,N〉4,λ∈R^1,μΠ0,f(x)是非负连续函数。  相似文献   

2.
提出了一个解二维抛的型方程初边值问题的简单实用的显格式,证明了其截断误差阶是O,稳定性条件是α+β≠1/2且max{α,β}≤1/4,其中,α=α.Δt/Δx^2.β=α.Δt/Δy^2。  相似文献   

3.
设(Xi,Yi)1≤i≤n为来自二元总体(X,Y)的平稳,φ-混合样本,记m(x)△E(Y│X=x),m(x)的一种递推型核估计为mn(x)=n∑i=1hi^-1Yik((x-Xi)/hi)/n∑j=1h^-1jk(x-Xj)/hj)。本文在一定的条件下证明了(n/(n∑j=1h^-1j)^1/2)(mn(x1)-m(x1),mn(x2)-m(x2),...mn(xr0)-m(xr0))′依分布收  相似文献   

4.
唐元生 《数学杂志》1994,14(2):211-216
将正整数n分拆成正整数的方法数记为g(n),本文对计数函数g(n)进行了均值估计。关于下限我们改进了[3]的结果。证明了对任意正整数k皆有Σn≤x1/ng(n)≥3(4log2 k!2k(k+1)/2)^-1xlog^kx,x≥1还获得了一个关于上限的结果Σn≤x1/ng(n)≤(k-1)!Σ^k-1n=01/n!x^1/k,x≥1。  相似文献   

5.
关于面积平均p叶函数(Ⅱ)   总被引:1,自引:0,他引:1  
董新汉 《数学进展》1993,22(5):441-448
假设f(z)=z^p(1+Σ^∞n=1an^z^nk)是△={|z|<1}内面积平均p叶的(如果必要,△={|z|<1}\(-1,0])。本文的主要结论是:(1)如果设M(r)=max|f(z)|,则(1-r)2p/kM(r)→αk≤1(r→1),αk=1的充要条件是f(z)=z^p(1-xz^k)^-2p/k,|x|=1。进一步,如果1≤k<4p,我们有|an|n^1-2p/k→αkГ(2p/k  相似文献   

6.
本文考虑如下的椭圆方程组△y+f(x,u)+Эu=0,x∈Ω △u+u-v=0,x∈Ω u=v=0,x∈ЭΩ 其中,Ω∈R^N(N≥3)是带光滑边界的有界区域,f(x,u)=h(x)u^α+u^β+λu^p,h(x)∈C^r(Ω)(0〈r〈1),α,β,p是正常数且0〈β〈α〈1〈p〈(N+2)/(N-2),λ,δ是正参数,由临界点理论证明了该方程组至少存在二对正解。  相似文献   

7.
本文用概率方法讨论了如下拟线性扩散方程的广义Dirichlet问题。 1/2△u(x)+q(x)u(x)+f(x,u)=au(x)/atx=(x,t{ limu(x)=q(z),z∈aD∩(D^c)^r且z为q连续。 其中D为d+1维欧氏空间R^d中的一个有界区域,aD的边界,q∈Kd,q在DHo  相似文献   

8.
对求解三维热传导方程利用待定参数法构造出一族对称的含参数的,截断误差为O(Δt^1+Δx^4+Δy^4+Δz^4)的便于计算的三层显格式,并讨论了其条件稳定性。  相似文献   

9.
该文讨论二维无界带形区域中Navier-Stokes方程(Ⅰ){ut-△u+uiэuэxi=-△p+f(x,t)∈Ω×R+(1)divu=0(2)u(X,t)∈(H^10(Ω)for t〉0(3)u(x,0)=u0(x)∈H(4)其中Ω=(0,d)×R,d〉0为一常数,u与p为未知量,其中u=(u1,u2)为速度场,p表示压力。我们证明了当u0∈H,f∈V且f「log(e+│x│^2)」^12∈L  相似文献   

10.
二维抛物型偏微分方程的绝对稳定显格式   总被引:1,自引:0,他引:1  
提出了一个解二维抛物型偏微分方程初边值问题的绝对稳定分支三层显式差分格式,格式的局部截断误差阶为O(△t2+△x2+△y2).实算表明,格式的稳定性能与理论分析是一致的.  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.
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   

17.
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   

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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号