Carnot群上水平Laplace算子的二次多项式算子的特征值不等式（英文）

本文研究了Carnot群上水平Laplace算子的二次多项式算子的Dirichlet特征值问题,并建立了一些特征值不等式.特别地,我们的结果涵盖了文献[10]对双调和水平Laplace算子所获得的结果.     

多项式Laplace算子的特征值估计

讨论了多项式Laplace算子Dirichlet问题,首先通过选取适当的函数,根据RayLeigh-Ritz不等式,得到了该问题用前k个特征值来估计第k+1个特征值的不等式,然后通过选取适当的系数,发现不等式蕴含成庆明和杨洪苍的结论及吴发恩和曹林芬的结论,且根据Chebyshev不等式等,证明了该不等式优于陈祖墀和钱春林的结论.     

各向异性次Laplace算子和拟p-次Laplace算子的Picone恒等式及其应用

本文首次把欧氏空间中的各向异性Laplace算子和拟p-Laplace算子分别引入到Heisenberg群Hn上,分别称为各向异性次Laplace算子和拟p-次Laplace算子,不仅建立它们相对应的Picone恒等式,而且还给出这些Picone恒等式的应用,从而把欧氏空间中的相关结果推广到Heisenberg群Hⁿ上.     

Heisenberg群上Laplace算子的离散谱

本文证明了Heisenberg群上Laplace算子的Dirichlet特征值的存在性，给出了特征值的估计     

Heisenberg群上Folland-Stein算子的Dirichlet特征值问题

该文研究Heisenberg群上Folland－Stein算子■（α为复数）的特征值问题，证明了当|Reα|＜n时，■具离散分布的特征值．当α∈（-n,n）时，特征值均为正的．然后给出了相邻特征值之差的估计．     

关于Heisenberg群上重sub—Laplace算子特征值的估计

对Ｈｅｉｓｅｎｂｅｒｇ群Ｈｎ上重ｓｕｂ－Ｌａｐｌａｃｅ算子的特征值问题Ｌ２ｕ＝λｕ，在Ω中，ｕ＝ｕγ＝０，在Ω上，讨论了特征值的估计，这里ΩＨｎ为有界域，具分片光滑边界，γ为Ω的单位外法向量．     

任意阶Laplace算子的特征值估计

设D为n维Euclid空间Rn的一个有界区域,且0＜λ1≤λ2≤…≤λk≤…是l阶Laplace算子的Dirichlet问题{(-△)lu=λu, 在D中,u=(e)u/(e)n=…=(e)l-1u/(e)nl-1=0,在(e)D上的特征值.得到了该问题用其前k个特征值来估计第(k+1)个特征值λk+1的不等式k∑i=1(λk+1-λi)≤1/n(4l(n+2l-2)]1/2{k∑i=1(λk+1-λi)1/2λil-1/lk∑i=1(λk+1-λi)1/2λi1/l}1/2,此不等式不依赖于区域D.对l≥3,上述不等式比所有已知的结果都要好.陈庆民与杨洪苍考虑了l=2的情形.我们的结果是他们结果的自然推广.当l=1时,我们的不等式蕴含杨洪苍不等式的弱形式.文中还给出了陈和杨的一个断言的直接证明.     

Heisenberg群上不变微分算子的特征值问题

讨论了Ｈｅｉｓｅｎｂｅｒｇ群Ｈｎ上一类不变微分算子Ｐ＝Σ↑ｍ↓ｌ＝０ａｌＬ＾ｌ的离散特征值的存在性。这里ａｌ〉０，ｌ＝０，１，…，ｍ，ｍ≥２。Ｌ为Ｈｎ上的ｓｕｂ－Ｌａｐｌａｃｅ算子。我们通过建立向量场的Ｐｏｉｎｃａｒｅ型不等式，结合Ｆｒｉｅｄｒｉｃｈｓ对欧氏空间上Ｌａｐｌａｃｅ算子的方法，得到了存在性结果。     

Kohn-Laplace算子的谱

设,其中α为一复参数.令Vo为在模下的完备化．把考虑为L2（Hn）中具定义域的无界算子时.本文给出了其谱的完整结果.     

A Liouville-type theorem on halfspaces for the Kohn Laplacian

Let be the Kohn Laplacian on the Heisenberg group and let be a halfspace of whose boundary is parallel to the center of . In this paper we prove that if is a non-negative -superharmonic function such that

then in .

     

An Inequality Between Dirichlet and Neumann Eigenvalues of the Heisenberg Laplacian

Let λ _k and μ _k be the eigenvalues of the Dirichlet and Neumann problems, respectively, in a domain of finite measure in ? ^d , d > 1. Filonov has proved in a simple way that the inequality μ _k+1 < λ _k holds for the Laplacian. We extend his result to the Heisenberg Laplacian in three-dimensional domains which fulfill certain geometric conditions.     

Heisenberg群上Folland—Stein定理的注记

该文在G．B．Folland与E．M．Stein研究的算子的基础上．拓展考虑了算子，其中λ＋μ≠0且λ≠α／2n，μ≠—α／2n），证明了：如果，使得有限（其中ψa，b，1（z，t）＝—4（λ＋μ）ab（｜z｜2＋1—it）a-1（｜z｜2＋1＋it）b-1，那么在分布的意义下将有．特别，当λ＝μ＝—1／2时，此结果即原来的Folland－Stein定理．     

Deleting Vertices and Interlacing Laplacian Eigenvalues

The authors obtain an interlacing relation between the Laplacian spectra of a graph G and its subgraph G - U, which is obtained from G by deleting all the vertices in the vertex subset U together with their incident edges. Also, some applications of this interlacing property are explored and this interlacing property is extended to the edge weighted graphs.     

Inequalities of Eigenvalues for the Dirac Operator on Compact Complex Spin Submanifolds in Complex Projective Spaces

For a compact complex spin manifold M with a holomorphic isometric embed- ding into the complex projective space,the authors obtain the extrinsic estimates from above and below for eigenvalues of the Dirac operator,which depend on the data of an isometric embedding of M.Further,from the inequalities of eigenvalues,the gaps of the eigenvalues and the ratio of the eigenvalues are obtained.     

On the Laplacian Eigenvalues of Signed Graphs

A signed graph is a graph with a sign attached to each edge. This article extends some fundamental concepts of the Laplacian matrices from graphs to signed graphs. In particular, the largest Laplacian eigenvalue of a signed graph is investigated, which generalizes the corresponding results on the largest Laplacian eigenvalue of a graph.     

Expansion of the Heisenberg Integral Mean via Iterated Kohn Laplacians: A Pizzetti-type Formula

A generalization and some applications of the so-called Pizzetti's Formula (which expresses the integral mean of a smooth function over an Euclidean ball as a power series w.r.t. the radius of the ball, having the iterated of the ordinary Laplace operator as coefficients) is given for , the Kohn Laplace operator on the Heisenberg group. A formula expressing the n-th power of is also proved. In the case of the ordinary Laplace operator, by Pizzetti's formula, we prove in a simple way that the only nonnegative polyharmonic functions are polynomials.     

给定阶与边独立数的树和单圈图的Laplacian矩阵的最大特征值

得到了给定顶点数和边独立数的树与单圈图的Laplacian矩阵的最大特征值的精确上界，并且给出了达到上界的所有极图．