带权散度型椭圆算子的低阶特征值估计

本文首先给出紧致带边(边界可以为空集)光滑度量测度空间上带权散度型算子的低阶特征值的一个一般不等式,通过使用这个一般不等式,可以得到光滑度量测度空间中有界连通区域上带权散度型算子的低阶特征值的一些万有不等式.     

Remarks on bifurcation for elliptic operators with odd nonlinearity

On estimating the eigenvalues for a class of semilinear elliptic operators, we obtain bifurcation and comparison results concerning the eigenvalues of some related linear problem.     

Verified numerical computations for multiple and nearly multiple eigenvalues of elliptic operators

In this paper, we propose a numerical method to verify bounds for multiple eigenvalues for elliptic eigenvalue problems. We calculate error bounds for approximations of multiple eigenvalues and base functions of the corresponding invariant subspaces. For matrix eigenvalue problems, Rump (Linear Algebra Appl. 324 (2001) 209) recently proposed a validated numerical method to compute multiple eigenvalues. In this paper, we extend his formulation to elliptic eigenvalue problems, combining it with a method developed by one of the authors (Jpn. J. Indust. Appl. Math. 16 (1998) 307).     

带势加权散度形式的 Grushin 型退化椭圆算子的 Dirichlet 特征值的上界*

本文考虑了带有位势的散度形式的 Grushin 型退化椭圆算子的 Dirichlet 加权特征值的估计.利 用傅里叶变换的方法得到了特征值的精确下界估计.然后通过试验函数的方法得到了特征值上界的杨型 不等式.     

Principal eigenvalues with indefinite weight functions

Both existence and non-existence results for principal eigenvalues of an elliptic operator with indefinite weight function have been proved. The existence of a continuous family of principal eigenvalues is demonstrated.

     

ASYMPTOTIC FORMULAE OF EIGENVALUE-COUNTING FUNCTION FOR ELLIPTIC EIGENVALUE PROBLEMS ON A BOUNDED DOMAIN WITH A FRACTAL BOUNDARY

IIntroductlonLet fi be a bounded open set In the n－dimensional Euclldean space R”withtheboundaryo0．In this paper,we shallessentiallydeal with thefollowingeigenvalue problem:,nD 一)。o…4km)螂川川J”人川川,x〔u,丸 人k＝1\“’“)llillj＝U．U b UI[。where丸 meanso/axj,and we suPPose that coeaclents aj。(x),J;k＝ 1,2;…,。satisfy the following conditions:(1)aj。(x)is real function and belong to Cm(R”);(2)There exists an M＞0;such that Iajk(x)l＜M;;;k二 1,2,…,n;148 Ann ofDiff Eqs Vol…     

On the matrix algebra of elliptic biquaternions

In this study, we introduce the concept of elliptic biquaternion matrices. Firstly, we obtain elliptic matrix representations of elliptic biquaternion matrices and establish a universal similarity factorization equality for elliptic biquaternion matrices. Afterwards, with the aid of these representations and this equality, we obtain various results on some basic topics such as generalized inverses, eigenvalues and eigenvectors, determinants, and similarity of elliptic biquaternion matrices. These valuable results may be useful for developing a perfect theory on matrix analysis over elliptic biquaternion algebra in the future.     

Inequalities for eigenvalues of elliptic operators in divergence form on Riemannian manifolds

In this paper, we study eigenvalues of elliptic operators in divergence form on compact Riemannian manifolds with boundary (possibly empty) and obtain a general inequality for them. By using this inequality, we prove universal inequalities for eigenvalues of elliptic operators in divergence form on compact domains of complete submanifolds in a Euclidean space, and of complete manifolds admitting special functions which include the Hadamard manifolds with Ricci curvature bounded below, a class of warped product manifolds, the product of Euclidean spaces with any complete manifold and manifolds admitting eigenmaps to a sphere.     

Estimates for eigenvalues of quasilinear elliptic systems. Part II

In this paper we find explicit lower bounds for Dirichlet eigenvalues of a weighted quasilinear elliptic system of resonant type in terms of the eigenvalues of a single p-Laplace equation. Also we obtain asymptotic bounds by studying the spectral counting function which is defined as the number of eigenvalues smaller than a given value.     

Unrestricted lower bounds for eigenvalues for classes of elliptic equations and systems of equations with applications to problems in elasticity

Lower bounds for the eigenvalues of some elliptic equations and elliptic systems over bounded regions are obtained. The bounds are universal in that they depend only upon the volume of the region. Specific applications include the clamped plate, the buckling problem for the clamped plate and the equations of linear elasticity. Our results are consequences of extensions of the methods of Li and Yau (Comm. Mat. Phys. 88 (1983) 309–318) who obtained such results for the eigenvalues of the fixed membrane problem.     

Spectral stability of general non-negative self-adjoint operators with applications to Neumann-type operators

We prove a stability theorem for the eigenvalues of general non-negative self-adjoint linear operators with compact resolvents and by applying it we prove a sharp stability result for the dependence of the eigenvalues of second order uniformly elliptic linear operators with homogeneous Neumann boundary conditions upon domain perturbation.     

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.     

Asymptotics of the eigenvalues of elliptic systems with fast oscillating coefficients

A singularly perturbed second-order elliptic operator with fast oscillating coefficients is considered in the whole space. Complete asymptotic expansions of the eigenvalues are constructed, which converge to the isolated eigenvalues of the homogenized operator; complete asymptotic expansions for the corresponding eigenfunctions are constructed as well.     

THE LOWER APPROXIMATION OF EIGENVALUE BY LUMPED MASS FINITE ELEMENT METHOD

In the present paper, we investigate properties of lumped mass finite element method (LFEM hereinafter) eigenvalues of elliptic problems. We propose an equivalent formulation of LFEM and prove that LFEM eigenvalues are smaller than the standard finite element method (SFEM hereinafter) eigenvalues. It is shown, for model eigenvalue problems with uniform meshes, that LFEM eigenvalues are not greater than exact solutions and that they are increasing functions of the number of elements of the triangulation, and numerical examples show that this result equally holds for general problems.     

Comparison theorems for eigenvalues

Summary Comparison theorems are proved relating the smallest positive eigenvalues λ and λ* of two operator equations of type Au=λBu and A*v=λ*B*v, respectively. Sufficient conditions on the operators are given which guarantee that λ⩽λ*, with special reference to the case that A and A* are elliptic differential operators. One novelty of the theory is that B is not required to be positive. Two general techniques are described: 1) A generalization of the classical minimum principle for eigenvalues, which is appropriate for selfadjoint elliptic operators A of arbitrary even order; and 2) A differential identity related to Picone's identity, appropriate for nonselfadjoint second order elliptic operators and strongly elliptic quasilinear systems. Entrata in Redazione il 24 maggio 1972.     

On the Moments of the Negative Eigenvalues of Elliptic Operators

We give an estimate for the moments of the negative eigenvalues of elliptic operators. The estimate is a generalization of Egorov-Kondrat'ev's estimate for elliptic operators. We use the j\varphi-transform decomposition of Frazier and Jawerth and techniques of harmonic analysis.     

Analytic continuation of eigenvalues of the Lamé operator

Eigenvalues of the Lamé operator are studied as complex-analytic functions in period τ of an elliptic function. We investigate the branching of eigenvalues numerically and clarify the relationship between the branching of eigenvalues and the convergent radius of a perturbation series.     

Inequalities for lower-order eigenvalues of a fourth-order elliptic operator

In this paper, we investigate the Dirichlet weighted eigenvalues problem of a fourth-order elliptic operator with variable coefficients on a bounded domain with smooth boundary in ? ⁿ . We establish some inequalities for lower-order eigenvalues of this problem. In particular, our results contain an inequality for eigenvalues of the biharmonic operator derived by Cheng, Huang, and Wei.     

Existence of a nontrivial solution for a class of hemivariational inequality problems at double resonance

In this paper, we discuss a class of semilinear elliptic hemivariational inequality problems. By using the nonsmooth minimax principle for locally Lipschitz functions, we establish the existence of a nontrivial solution for the semilinear elliptic hemivariational inequality problem, where incomplete double resonance occurs at infinity between two distinct consecutive eigenvalues.     

ON THE DIFFERENCE OF CONSECUTIVE EIGENVALUES OF UNIFORMLY ELLIPTIC OPERATORS OF HIGHER ORDERS

This paper considers the upper bound for the difference of consecutive eigenvalues of a class of uniformly elliptic operators of higher orders. The upper bound of $\lambda _{n+1}-\lambda _n$ is dependent on the first n - 1 eigenvalues and the coefficients in equations.