树的第二个最大特征值

本文得到了边独立数为n且阶为2n+2的树的第二个最大特征值的精确上界,且给出了达到上界的所有的极树.     

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．     

补图是树的图的距离拉普拉斯特征值（英文）

一个连通图的距离拉普拉斯矩阵定义为顶点传输度对角矩阵与距离矩阵的差,距离拉普拉斯矩阵的特征值称为这个图的距离拉普拉斯特征值.距离拉普拉斯伸展度定义为图的最大与次小距离拉普拉斯特征值的差.本文确定了补图的最大距离拉普拉斯特征值取得最小值和最大值的树及补图的次小距离拉普拉斯特征值取得最小值和最大值的树,也确定了补图的次大距离拉普拉斯特征值取得最小值的树,还确定了补图的距离拉普拉斯伸展度取得最小值和最大值的树.     

树的第二大特征值的界

在文献Ji-Ming Guo,Shang-Wang Tan.A conjecture on the second largest eigenvalue of a tree with perfect matchings.Linear Algebra and its Applications,2002,347(1-3):9-15和Ji-Ming Guo,Shang-Wang Tan.A note on the second largest eigenvalue of a tree with perfect matchings.Linear Algebra and Its Applications,2004,380:125-134中,Guo和Tan给出了有2k个顶点且有完美匹配的树的第二大特征值的上界,这个上界与顶点数有关,并且刻画了第二大特征值达到该上界的树.本文给出了有2k个顶点的树的第二大特征值的上界,这个上界与顶点数和最大匹配的基数有关,并且刻画了第二大特征值达到该上界的树.     

四阶不完全对称张量M-特征值的新包含域及应用

四阶不完全对称张量的M-特征值在非线性弹性材料分析中有着广泛的应用.本文的目的是给出四阶不完全对称张量M-特征值的新包含域,得到最大M-特征值上界更精确的估计,并将得到的上界估计值应用到计算最大M-特征值的WQZ算法中,数值例子验证了结果的有效性.最后,基于得到的包含域,给出了四阶不完全对称张量正定性判定的充分条件.     

多参数二次特征值问题重特征值的灵敏度分析

本文研究解析依赖于多参数的二次特征值问题重特征值的灵敏度分析,得到了重特征值的方向导数,证明了相应的特征向量矩阵和特征值平均值的解析性,给出了其一阶偏导数的表达式．然后以这些结论为基础,定义了二次特征值问题重特征值及其不变子空间的灵敏度,并给出了确定二次特征值问题所含矩阵中敏感元素的方法．     

Halin图谱半径的新上界及极图

利用移接变形的方法再结合特征值的计算技巧刻画出Halin图中谱半径达到第二大的极图,从而得到除轮图以外的Halin图的谱半径的上界以及极图.     

一类双中心平面二次系统的Abel积分零点个数

利用Abel积分与第一、第二型完全椭圆积分,本文研究一类具有两个中心奇点的平面二次系统在n次小扰动下的Abel积分零点个数上界问题,得到了较小的上界估计．     

连通图拟拉普拉斯矩阵的最大特征值

用代数方法给出了一个关于连通图顶点度数的不等式,并给出了连通图拟拉普拉斯矩阵的最大特征值的几个上界.     

多部有向图的最大特征值

本讨论了多部有向图最大特征值的上界,并且给出了达到上界的充分且必要条件,从而推广了「２」,「３」和「４」的结论。     

Graphs and Hermitian matrices: Exact interlacing

We prove conditions for equality between the extreme eigenvalues of a matrix and its quotient. In particular, we give a lower bound on the largest singular value of a matrix and generalize a result of Finck and Grohmann about the largest eigenvalue of a graph.     

Eigenvalue estimates of the p-Laplacian on finite graphs

In this paper, we study the eigenvalue of p-Laplacian on finite graphs. Under generalized curvature dimensional condition, we obtain a lower bound of the first nonzero eigenvalue of p-Laplacian. Moreover, a upper bound of the largest p-Laplacian eigenvalue is derived.     

Hermitian forms and the large and small sieves

The author observes that two Hermitian forms have the same largest eigenvalue. A large sieve result of Roth-Bombieri type and Selberg's upper bound sieve with a Montgomery type error term are derived.     

树型代数拟遗传序的组合公式及其算法

本文给出了树型代数的拟遗传序数的精确上界以及单生成元的树型代数的拟遗传序数的精确下界及其算法 ,并由此得到一个新的组合公式 .     

Some results on the Laplacian eigenvalues of unicyclic graphs

In this paper, we provide the smallest value of the second largest Laplacian eigenvalue for any unicyclic graph, and find the unicyclic graphs attaining that value. And also give an “asymptotically good” upper bounds for the second largest Laplacian eigenvalues of unicyclic graphs. Using this results, we can determine unicyclic graphs with maximum Laplacian separator. And unicyclic graphs with maximum Laplacian spread will also be determined.     

向量优化中有效点的存在性

分别在有pre-order的无线性结构的集合和拓扑空间中，给出了有效点的存在性。作为应用，讨论了向量优化问题中解的存在性。最后给出了紧、弱紧、锥紧、锥半紧、上序紧、下序紧、上序半紧、准上序半紧和准下序半紧等之间的关系。     

Graphs with three distinct eigenvalues and largest eigenvalue less than 8

In this paper we consider graphs with three distinct eigenvalues and, we characterize those with the largest eigenvalue less than 8. We also prove a simple result which gives an upper bound on the number of vertices of graphs with a given number of distinct eigenvalues in terms of the largest eigenvalue.     

Bounds for the second largest eigenvalue of a transition matrix

We find an upper bound, with general form, for the second largest eigenvalue of a transition matrix; special cases of which have previously been proposed as upper bounds and others which are new improvements.     

Backward error analysis for linearizations in heavily damped quadratic eigenvalue problem

Heavily damped quadratic eigenvalue problem (QEP) is a special type of QEPs. It has a large gap between small and large eigenvalues in absolute value. One common way for solving QEP is to linearize the original problem via linearizations. Previous work on the accuracy of eigenpairs of not heavily damped QEP focuses on analyzing the backward error of eigenpairs relative to linearizations. The objective of this paper is to explain why different linearizations lead to different errors when computing small and large eigenpairs. To obtain this goal, we bound the backward error of eigenpairs relative to the linearization methods. Using these bounds, we build upper bounds of growth factors for the backward error. We present results of numerical experiments that support the predictions of the proposed methods.