Asymptotics of eigenvalues for regular Sturm-Liouville problems with eigenvalue parameter in the boundary condition

In this paper we obtain asymptotic estimates of eigenvalues for regular Sturm-Liouville problems having the eigenparameter in the boundary condition. The method is based on an iterative procedure solving the associated Riccati equation and producing an asymptotic expansion of the solution in the higher powers of 1/λ1/2 as λ→∞.     

Asymptotics of shell eigenvalue problems

The asymptotic behaviour of the smallest eigenvalue in linear shell problems is studied, as the thickness parameter tends to zero. When pure bending is not inhibited, such a behaviour has been essentially studied by Sanchez-Palencia. When pure bending is inhibited, the situation is more complex and some information can be obtained by using the Real Interpolation Theory. In order to cover the widest range of mid-surface geometry and boundary conditions, an abstract approach has been followed. A result concerning the ratio between the bending and the total elastic energy is also announced. To cite this article: L. Beirão da Veiga, C. Lovadina, C. R. Acad. Sci. Paris, Ser. I 342 (2006).     

Asymptotics of the eigenvalues of Sturm-Liouville problem

We prove a new asymptotic formula for the eigenvalues of Sturm-Liouville problem with summable potential. The obtained result extends and make more precise previously known formulas, and takes into account the smooth dependence of the spectral data on boundary conditions.     

Continuation of eigenvalues and invariant pairs for parameterized nonlinear eigenvalue problems

Invariant pairs have been proposed as a numerically robust means to represent and compute several eigenvalues along with the corresponding (generalized) eigenvectors for matrix eigenvalue problems that are nonlinear in the eigenvalue parameter. In this work, we consider nonlinear eigenvalue problems that depend on an additional parameter and our interest is to track several eigenvalues as this parameter varies. Based on the concept of invariant pairs, a theoretically sound and reliable numerical continuation procedure is developed. Particular attention is paid to the situation when the procedure approaches a singularity, that is, when eigenvalues included in the invariant pair collide with other eigenvalues. For the real generic case, it is proven that such a singularity only occurs when two eigenvalues collide on the real axis. It is shown how this situation can be handled numerically by an appropriate expansion of the invariant pair. The viability of our continuation procedure is illustrated by a numerical example.     

A nonlinear eigenvalue problem arising in a nanostructured quantum dot

In this paper we investigate a minimization problem related to the principal eigenvalue of the s-wave Schrödinger operator. The operator depends nonlinearly on the eigenparameter. We prove the existence of a solution for the optimization problem and the uniqueness will be addressed when the domain is a ball. The optimized solution can be applied to design new electronic and photonic devices based on the quantum dots.     

Perturbation method for solving the nonlinear eigenvalue problem arising from fatigue crack growth problem in a damaged medium

An analytical solution of the nonlinear eigenvalue problem arising from the fatigue crack growth problem in a damaged medium in coupled formulation is obtained. The perturbation technique for solving the nonlinear eigenvalue problem is used. The method allows to find the analytical formula expressing the eigenvalue as the function of parameters of the damage evolution law. It is shown that the eigenvalues of the nonlinear eigenvalue problem are fully determined by the exponents of the damage evolution law. In the paper the third-order (four-term) asymptotic expansions of the angular functions determining the stress and continuity fields in the neighborhood of the crack tip are given. The asymptotic expansions of the angular functions permit to find the closed-form solution for the problem considered.     

Asymptotics of eigenvalues of A regular boundary-value problem

We study a boundary-value problem x ⁽ⁿ⁾ + Fx = λx, U _h(x) = 0, h = 1,..., n, where functions x are given on the interval [0, 1], a linear continuous operator F acts from a Hölder space H ^y into a Sobolev space W ₁ ^n+s , U _h are linear continuous functional defined in the space $H^{k_h } $ , and k _h ≤ n + s - 1 are nonnegative integers. We introduce a concept of k-regular-boundary conditions U _h(x)=0, h = 1, ..., n and deduce the following asymptotic formula for eigenvalues of the boundary-value problem with boundary conditions of the indicated type: $\lambda _v = \left( {i2\pi v + c_ \pm + O(|v|^\kappa )} \right)^n $ , v = ± N, ± N ± 1,..., which is true for upper and lower sets of signs and the constants κ≥0 and c _± depend on boundary conditions.     

A Jacobi-Davidson method for two real parameter nonlinear eigenvalue problems arising from delay differential equations

The critical delays of a delay-differential equation can be computed by solving a nonlinear two-parameter eigenvalue problem. For large scale problems, we propose new correction equations for a Jacobi-Davidson type method, that also forces real valued critical delays. We present two different equations: one complex valued equation using a direct linear system solver, and one Jacobi-Davidson style correction equation which is suitable for an iterative linear system solver. A numerical example of a large scale problem arising from PDEs shows the effectiveness of the method. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Multiple solutions of constant sign for nonlinear nonsmooth eigenvalue problems near resonance

In this paper we study a class of nonlinear elliptic eigenvalue problems driven by the p-Laplacian and having a nonsmooth locally Lipschitz potential. We show that as the parameter approaches (= the principal eigenvalue of ) from the right, the problem has three nontrivial solutions of constant sign. Our approach is variational based on the nonsmooth critical point theory for locally Lipschitz functions. In the process of the proof we also establish a generalization of a recent result of Brezis and Nirenberg for C₀¹ versus W₀^1,p minimizers of a locally Lipschitz functional. In addition we prove a result of independent interest on the existence of an additional critical point in the presence of a local minimizer of constant sign. Finally by restricting further the asymptotic behavior of the potential at infinity, we show that for all the problem has two solutions one strictly positive and the other strictly negative.Received: 7 January 2003, Accepted: 12 May 2003, Published online: 4 September 2003Mathematics Subject Classification (2000): 35J20, 35J85, 35R70     

A linear eigenvalue algorithm for the nonlinear eigenvalue problem

The Arnoldi method for standard eigenvalue problems possesses several attractive properties making it robust, reliable and efficient for many problems. The first result of this paper is a characterization of the solutions to an arbitrary (analytic) nonlinear eigenvalue problem (NEP) as the reciprocal eigenvalues of an infinite dimensional operator denoted ${\mathcal {B}}$ . We consider the Arnoldi method for the operator ${\mathcal {B}}$ and show that with a particular choice of starting function and a particular choice of scalar product, the structure of the operator can be exploited in a very effective way. The structure of the operator is such that when the Arnoldi method is started with a constant function, the iterates will be polynomials. For a large class of NEPs, we show that we can carry out the infinite dimensional Arnoldi algorithm for the operator ${\mathcal {B}}$ in arithmetic based on standard linear algebra operations on vectors and matrices of finite size. This is achieved by representing the polynomials by vector coefficients. The resulting algorithm is by construction such that it is completely equivalent to the standard Arnoldi method and also inherits many of its attractive properties, which are illustrated with examples.     

Recovery of interior eigenvalues from reduced near field data

We consider inverse obstacle and transmission scattering problems where the source of the incident waves is located on a smooth closed surface that is a boundary of a domain located outside of the obstacle/inhomogeneity of the media. The domain can be arbitrarily small but fixed.The scattered waves are measured on the same surface. An effective procedure is suggested for recovery of interior eigenvalues by these data.     

Asymptotics of the eigenvalues of the Sturm-Liouville problem with discrete self-similar weight

We study the asymptotics of the spectrum of the boundary-value problem $$ - y'' - \lambda \rho y = 0,y(0) = y(1) = 0 $$ for the case in which the weight ρ ∈ W? ₂ ^?1 [0, 1] is the generalized (in the sense of distributions) derivative of a self-similar function P ∈ L ₂[0, 1] of zero spectral order.     

Branching from degenerate solutions of a nonlinear eigenvalue problem

When a confined material undergoes a thermal reaction, the steady-state temperature distribution within the body is governed by a partial differential equation of elliptic type, at least when reactant consumption is neglected. The behaviour of the solution set of this nonlinear eigenvalue problem as parameters are varied can have important consequences for the evolution of the corresponding time-dependent equation. In this paper, the Lyapunov-Schmidt reduction is used to describe the solutions in the neighbourhood of degenerate points at which the temperature need not depend smoothly on the thermal parameters. Quite diverse behaviour is found, depending on the precise nature of the degenerate point.     

On the computation of all eigenvalues for the eigenvalue complementarity problem

In this paper, a parametric algorithm is introduced for computing all eigenvalues for two Eigenvalue Complementarity Problems discussed in the literature. The algorithm searches a finite number of nested intervals \([\bar{l}, \bar{u}]\) in such a way that, in each iteration, either an eigenvalue is computed in \([\bar{l}, \bar{u}]\) or a certificate of nonexistence of an eigenvalue in \([\bar{l}, \bar{u}]\) is provided. A hybrid method that combines an enumerative method [1] and a semi-smooth algorithm [2] is discussed for dealing with the Eigenvalue Complementarity Problem over an interval \([\bar{l}, \bar{u}]\) . Computational experience is presented to illustrate the efficacy and efficiency of the proposed techniques.     

On the eigenvalues of a nonlinear spectral problem

We consider a nonlinear eigenvalue problem of the Sturm–Liouville type with conditions of the third kind, which describes the propagation of polarized electromagnetic waves in a plane dielectric waveguide. The equation is nonlinear in the unknown function, and the boundary conditions depend on the spectral parameter nonlinearly. We obtain an equation for the spectral parameter and formulas for the zeros of the eigenfunctions and show that the problem has at most finitely many isolated eigenvalues.     

Sensitivity analysis of semi-simple eigenvalues of regular quadratic eigenvalue problems

This paper discusses the sensitivity analysis of semisimple eigenvalues and associated eigen-matrix triples of regular quadratic eigenvalue problems analytically dependent on several parameters. The directional derivatives of semisimple eigenvalues are obtained. The average of semisimple eigenvalues and corresponding eigen-matrix triple are proved to be analytic, and their partial derivatives are given. On these grounds, the sensitivities of the semisimple eigenvalues and corresponding eigenvector matrices are defined.     

Asymptotics of negative eigenvalues of the Dirichlet problem with the density changing sign

In a three-dimensional anisotropic elastic space with either a bounded foreign inclusion or a void, we derive asymptotic formulas for the increment of the polarization tensor of a defect caused by a smooth variation of the defect boundary. The formulas involve weighted integrals of jumps of the surface enthalpy evaluated for solutions to the problem about deformation of an unperturbed composite space by constant stress at infinity. The study of the positiveness/negativeness of the polarization matrix increment leads to inferences with a clear physical interpretation, in particular, for elastic solids admitting phase transitions. For homogeneous ellipsoid shaped inclusions we derive a relation between the polarization tensor and the Eshelby tensor and obtain miscellaneous consequences of this relation as well. In particular, we introduce the notion of the link tensor which is symmetric and positive definite for any elastic properties of homogeneous materials of the composite space. Bibliography: 60 titles. Illustrations: 5 figures. Dedicated to Nina Nikolaevna Uraltseva Translated from Problemy Matematicheskogo Analiza, 41, May 2009, pp. 3–36.