Effet tunnel pour des puits sous-variétés
Efficient bounds for the spectral shift function
Eigensystem of an L 2-perturbed harmonic oscillator is an unconditional basis
For any complex valued L p-function b(x), 2 ≤ p < ∞, or L ∞-function with the norm ‖b↾L ∞‖ < 1, the spectrum of a perturbed harmonic oscillator operator L = −d 2/dx 2 + x 2 + b(x) in L 2(ℝ1) is discrete and eventually simple. Its SEAF (system of eigen- and associated functions) is an unconditional basis in L 2(ℝ).
Eigenvalue approximation
Eigenvalues and subelliptic estimates for non-selfadjoint semiclassical operators with double characteristics
For a class of non-selfadjoint –pseudodifferential operators with double characteristics, we give a precise description of the spectrum and establish accurate semiclassical resolvent estimates in a neighborhood of the origin. Specifically, assuming that the quadratic approximations of the principal symbol of the operator along the double characteristics enjoy a partial ellipticity property along a suitable subspace of the phase space, namely their singular space, we give a precise description of...
Ein „merkwürdiges” Spektrum für nichtlineare Operatoren
We define a spectrum for Lipschitz continuous nonlinear operators in Banach spaces by means of a certain kind of "pseudo-adjoint" and study some of its properties.
Elementary linear algebra for advanced spectral problems
We describe a simple linear algebra idea which has been used in different branches of mathematics such as bifurcation theory, partial differential equations and numerical analysis. Under the name of the Schur complement method it is one of the standard tools of applied linear algebra. In PDE and spectral analysis it is sometimes called the Grushin problem method, and here we concentrate on its uses in the study of infinite dimensional problems, coming from partial differential operators of mathematical...
Entropy and Eigenvalues of Certain Integral Operators.
Equicontinuous families of operators generating mean periodic maps
The existence of mean periodic functions in the sense of L. Schwartz, generated, in various ways, by an equicontinuous group or an equicontinuous cosine function forces the spectral structure of the infinitesimal generator of or . In particular, it is proved under fairly general hypotheses that the spectrum has no accumulation point and that the continuous spectrum is empty.
Equivalence of Boundary Eigenvalue Operator Fuctions and their Characteristic Matrix Functions.
Erratum to “Non-trapping condition for semiclassical Schrödinger operators with matrix-valued potentials”.
Essential descent spectrum and commuting compact perturbations.
Essential spectra of quasisimilar -quasihyponormal operators.
Estimates for a number of negative eigenvalues of the Schrödinger operator with intensive magnetic field
Estimations de l'effet tunnel pour le double-puits
Étude d'une fonction remarquable associée aux moyennes de convolution
Dans cet article nous étudions la série génératrice des poids alternés d’une moyenne de convolution induite par un processus de diffusion. Nous montrons que celle-ci est une fonction méromorphe, naturellement liée à un certain opérateur compact. Cette fonction est simplement égale à , lorsque le déterminant de Fredholm de cet opérateur existe, et nous la précisons dans les autres cas.
Examples of stable -semigroups
Exemples de noyaux admettant des resolvantes.
Exponential stability of linear and almost periodic systems on Banach spaces.
Exponentials of bounded normal operators
The present paper is mainly concerned with equations involving exponentials of bounded normal operators. Conditions implying commutativity of normal operators are given, without using the known 2πi-congruence-free hypothesis. This is a continuation of a recent work by the second author.