Estimates for the Classical Parametrix for the Laplacian.
Expansions and eigenfrequencies for damped wave equations
We study eigenfrequencies and propagator expansions for damped wave equations on compact manifolds. In the strongly damped case, the propagator is shown to admit an expansion in terms of the finitely many eigenmodes near the real axis, with an error exponentially decaying in time. In the presence of an elliptic closed geodesic not meeting the support of the damping coefficient, we show that there exists a sequence of eigenfrequencies converging rapidly to the real axis. In the case of Zoll manifolds,...
Finite eigenfunction approximations for continuous spectrum operators.
Fundamental Solutions and Eigenfunction Expansions for Schrödinger Operators . I. Fundamental Solutions.
Fundamental Solutions and Eigenfunction Expansions for Schrödinger Operators. II. Eigenfunction Expansions.
Generalized eigenfunctions of relativistic Schrödinger operators in two dimensions.
Green's function and convergence of Fourier series for elliptic differential operators with potential from Kato space.
Hearing the shape of membranes: Further results.
Heat-diffusion and Poisson integrals for Laguerre and special Hermite expansions on weighted spaces
We investigate heat-diffusion and Poisson integrals associated with Laguerre and special Hermite expansions on weighted spaces with weights.
Instability of oscillations in cable-stayed bridges
In this paper the stability of two basic types of cable stayed bridges, suspended by one or two rows of cables, is studied. Two linearized models of the center span describing the vertical and torsional oscillations are investigated. After the analysis of these models, a stability criterion is formulated. The criterion expresses a relation between the eigenvalues of the vertical and torsional oscillations of the center span. The continuous dependence of the eigenvalues on some data is studied and...
- theory for a class of singular elliptic differential operators, II
L'equazione . Teoremi di completezza
In ipotesi molto generali si dimostrano teoremi di completezza nel senso di Picone per l'equazione (1). Come corollario si ottengono teoremi del tipo Runge.
Localization of Spherical Harmonic Expansions.
Mathematical Aspects of 'T Hooft's Eigenvalue Problem in Two-Dimensional Quantum Chromodynamics. Part I. A variational approach, and nodal properties of the eigenfunctions.
Noncoercive boundary value problems for the Lapace equation with a spectral parameter.
Nonconforming finite element approximations of the Steklov eigenvalue problem and its lower bound approximations
The paper deals with error estimates and lower bound approximations of the Steklov eigenvalue problems on convex or concave domains by nonconforming finite element methods. We consider four types of nonconforming finite elements: Crouzeix-Raviart, , and enriched Crouzeix-Raviart. We first derive error estimates for the nonconforming finite element approximations of the Steklov eigenvalue problem and then give the analysis of lower bound approximations. Some numerical results are presented to...
On an oblique derivative problem involving an indefinite weight
In this paper we derive results concerning the angular distrubition of the eigenvalues and the completeness of the principal vectors in certain function spaces for an oblique derivative problem involving an indefinite weight function for a second order elliptic operator defined in a bounded region.
On eigenvalues and eigenfunctions of an operational equation
On Riesz means of eigenfunction expansions for the Kohn-Laplacian.
On some properties of eigenvalues and eigenfunctions of certain differential equations of the fourth order