Yamabe流上的Laplace算子的第一特征值

首先建立了在Yamabe流上的Laplace算子的第一特征值的演化公式.作为其应用,在非规范化的Yamabe流上,得到了关于第一特征值的一些有趣的单调量(不减或不增).然后,研究了在规范化的Yamabe流上的第一特征值的渐近行为,并且给出了第一特征值的渐近上界的一个直接证明.     

一类Sturm-Liouville问题特征的渐近分析

考虑[0,1]上带第三类边界条件的S-L问题特征值的渐近表示.利用已有的渐近性结果及Fr啨chet导数技术,对特征值进行了精细的分析,清楚地给出了边界条件中的常数(h,H)对特征值的影响.本文的工作对S-L问题的一类反谱问题及相关微分方程反问题的唯一性结果有着重要的应用,也为专著[4,6]中的某些关键结果提供了一个简化的证明途径.     

三维区域上Qrot1元的渐近展开及外推

本文研究了正方体区域上Qrot1非协调元渐近展开式.利用林群、吕涛等提出的有限元误差渐近展开法,获得了正方体区域上Qrot1非协调元特征值的误差渐近展开式.理论分析和数值实验结果表明三维Qrot1非协渊元特征值外推公式是有效的,可以把特征值的精度从二阶提高到四阶.     

三维区域上Q_1~(rot)元的渐近展开及外推

本文研究了正方体区域上Q₁^rot非协调元渐近展开式.利用林群、吕涛等提出的有限元误差渐近展开法,获得了正方体区域上Q₁^rot非协调元特征值的误差渐近展开式.理论分析和数值实验结果表明三维Q₁^rot非协调元特征值外推公式是有效的,可以把特征值的精度从二阶提高到四阶.     

树上生灭过程的Dirichlet特征值估计

本文给出树上两类非常返的生灭过程的第一Dirichlet特征值的变分公式．一类是配称测度有限时,给出以根为吸收点的Dirichlet特征值的变分公式;另一类是配称测度无限时,给出树上生灭过程的Dirichlet主特征值的变分公式．     

第一特征值对偶变分公式的分析证明(一维情形) *

第一非零特征值是自共轭算子谱的主项 ,在各种应用中起着重要作用 .关于此特征值 ,有熟知的变分公式 (称为极大极小原理 ) ,它对于上界估计特别有效 .对于下界估计的新的对偶变分公式 ,就一维情形给出分析证明 (原来的证明使用的是概率方法 ) ,并作了若干扩充 .     

树上p-Laplacian算子的第一混合特征值

本文研究了树上以唯一根为Dirichlet边界的离散加权p-Laplacian算子的第一特征值问题,该特征值亦为一类加权Hardy不等式的最优常数.通过研究此特征值对应的特征函数的性质,给出具有混合边界的特征值的三种变分公式,该结果可以看做经典变分公式的重要补充.作为应用,给出了此特征值的上、下界的基本估计,并给用两个例子例证相关结果.     

一维Dirac方程组的几个迹公式

本文用回路族上的渐近估计方法,获得了一维Dirac方程组在有限区间自伴边值条件,周期条件以及非局部边值条件下特征值问题的迹公式。     

一维情形第一特征值的变分公式及逼近定理

给出了一维椭圆算子和一类 Markov 链的第一特征值的完全变分公式和逼近程序.     

一类正则Sturm—Liouville问题特征的渐近分析

考虑[0,π]上一类带一般分离型边界条件的正则Sturm—Liouville问题特征的渐近表示,利用Frechet导数,对特征值进行精细的分析,清楚地给出了方程系数q（x）及边界条件中常数cot α,col β对特征值的影响．使结论更具一般化．     

A correction method for finding lower bounds of eigenvalues of the second‐order elliptic and Stokes operators

In this paper, for the second‐order elliptic and Stokes eigenvalue problems with variable coefficients, we propose a correction method to nonconforming eigenvalue approximations and prove that the corrected eigenvalues converge to the exact ones asymptotically from below. In particular, the asymptotic lower bound property of corrected eigenvalues is always valid whether the eigenfunctions are smooth or singular. Finally, we prove that the convergence order of corrected eigenvalues is still the same as that of uncorrected eigenvalues.     

Stokes特征值问题Q_1元的展开式及其外推

考虑利用Q1元来求解Stokes特征值问题的误差渐进展开式,并以此为基础进行外推获得高精度.     

输运方程特征值问题的高精度求积方法

<正>1引言考虑平板各向异性散射和裂变的输运方程:其中,2a为平板厚度.-a≤x≤a,-1≤μ,μ′≤1,V是临界特征值.如何求解输运方程的最大的简单特征值问题是一个重要课题[1].关于它的存在性已     

一类Dirac方程特征值问题的迹恒等式

讨论了带有非局部边界条件的一维Dirac方程BdY/dx+P(x)Y=λY的特征值问题,其中首先建立了问题的特征值集合与一个整函数u(λ)零点集合的对应,并对Dirac算子的特征值进行了估计,然后借助于一个积分恒等式,采用留数方法,得到了该问题的特征值的迹恒等式.     

A SINGULARLY PERTURBED EIGENVALUE ROBIN PROBLEM WITH TURNING POINT OF HIGHER ORDER

A singularly perturbed eigenvalue Robin problem with turning point of higher order is studied, which can describe some heat conduction phenomena. Using the method of Langer transformation, the uniformly asymptotic solution of the equation is obtained, which is expressed by Bessel function, and the eigenvalue and eigenfunction of the problem are given, and then the known result is generalized.     

Local Perturbations of the Schrödinger Operator on the Plane

We obtain necessary and sufficient conditions for the appearance of a small eigenvalue of the Schrödinger operator on the plane under local operatorial excitations. In the case where the small eigenvalue exists, we construct its asymptotic behavior. We present examples.     

Extrapolation of Mixed Finite Element Approximations for the Maxwell Eigenvalue Problem

In this paper,a general method to derive asymptotic error expansion formulas for the mixed finite element approximations of the Maxwell eigenvalue problem is established.Abstract lemmas for the error of the eigenvalue approximations are obtained.Based on the asymptotic error expansion formulas,the Richardson extrapolation method is employed to improve the accuracy of the approximations for the eigenvalues of the Maxwell system from θ(h2) to θ(h4) when applying the lowest order Nédé1ec mixed finite element and a nonconforming mixed finite element.To our best knowledge,this is the first superconvergence result of the Maxwell eigenvalue problem by the extrapolation of the mixed finite element approximation.Numerical experiments are provided to demonstrate the theoretical results.     

Characteristic frequencies of bodies with thin spikes III. Frequency splitting

The eigenvalue problem for the Laplace operator with the Neumann boundary conditions in a domain that has a thin spike of finite length is considered for the case in which the limit value is an eigenvalue both for the main body and the spike. The method of matched asymptotic expansions is used to construct total asymptotics of the eigenvalues of the perturbed problem and obtain closed formulas for the leading asymptotic terms. Translated fromMatematicheskie Zametki, Vol. 61, No. 4, pp. 494–502, April, 1997. Translated by V. E. Nazaikinskii     

Minimization of the ground state of the mixture of two conducting materials in a small contrast regime

We consider the problem of distributing two conducting materials with a prescribed volume ratio in a given domain so as to minimize the first eigenvalue of an elliptic operator with Dirichlet conditions. The gap between the two conductivities is assumed to be small (low contrast regime). For any geometrical configuration of the mixture, we provide a complete asymptotic expansion of the first eigenvalue. We then consider a relaxation approach to minimize the second‐order approximation with respect to the mixture. We present numerical simulations in dimensions two and three to illustrate optimal distributions and the advantage of using a second‐order method. Copyright © 2016 John Wiley & Sons, Ltd.