A counterexample to a compact embedding theorem for functions with values in a Hilbert space.
A Fredholm Determinant Theory for p-Summing Maps in Banach Spaces.
A new method for the obtaining of eigenvalues of variational inequalities of the special type (Preliminary communication)
A non elliptic spectral problem related to the analysis of superconducting micro-strip lines
This paper is devoted to the spectral analysis of a non elliptic operator , deriving from the study of superconducting micro-strip lines. Once a sufficient condition for the self-adjointness of operator has been derived, we determine its continuous spectrum. Then, we show that is unbounded from below and that it has a sequence of negative eigenvalues tending to . Using the Min-Max principle, a characterization of its positive eigenvalues is given. Thanks to this characterization, some conditions...
A non elliptic spectral problem related to the analysis of superconducting micro-strip lines
This paper is devoted to the spectral analysis of a non elliptic operator A , deriving from the study of superconducting micro-strip lines. Once a sufficient condition for the self-adjointness of operator A has been derived, we determine its continuous spectrum. Then, we show that A is unbounded from below and that it has a sequence of negative eigenvalues tending to -∞. Using the Min-Max principle, a characterization of its positive eigenvalues is given. Thanks to this characterization, some...
A problem in Rayleigh-Taylor instability
A spectral study of an infinite axisymmetric elastic layer
We present here a theoretical study of eigenmodes in axisymmetric elastic layers. The mathematical modelling allows us to bring this problem to a spectral study of a sequence of unbounded self-adjoint operators , , in a suitable Hilbert space. We show that the essential spectrum of is an interval of type and that, under certain conditions on the coefficients of the medium, the discrete spectrum is non empty.
A spectral study of an infinite axisymmetric elastic layer
We present here a theoretical study of eigenmodes in axisymmetric elastic layers. The mathematical modelling allows us to bring this problem to a spectral study of a sequence of unbounded self-adjoint operators An, , in a suitable Hilbert space. We show that the essential spectrum of An is an interval of type and that, under certain conditions on the coefficients of the medium, the discrete spectrum is non empty.
A way of estimating the convergence rate of the Fourier method for PDE of hyperbolic type
The Fourier expansion in eigenfunctions of a positive operator is studied with the help of abstract functions of this operator. The rate of convergence is estimated in terms of its eigenvalues, especially for uniform and absolute convergence. Some particular results are obtained for elliptic operators and hyperbolic equations.
Absolutely continuous and singular spectral shift functions [Book]
Approximate determination of eigenvalues and eigenvectors of selfadjoint operators
Bloch waves for a solid-fluid mixture
Completeness and sequential completeness in certain spaces of measures
Convergence of approximation methods for eigenvalue problem for two forms
The paper concerns an approximation of an eigenvalue problem for two forms on a Hilbert space . We investigate some approximation methods generated by sequences of forms and defined on a dense subspace of . The proof of convergence of the methods is based on the theory of the external approximation of eigenvalue problems. The general results are applied to Aronszajn’s method.
Convergence of generalized eigenfunction expansions.
Decomposition of operators with countable spectrum.
Sufficient spectral conditions for the existence of a spectral decomposition of an operator T defined on a Banach space X, with countable spectrum, are given. We apply the results to obtain the West decomposition of certain Riesz operators.
Description lagrangienne d'un boson scalaire à l'aide d'un triplet nucléaire
Direct Integrals of Left Hubert Algebras.
Eigenspaces of Families of Toeplitz Operators with Rational Matrix Symbols
Erratum/addendum to the paper: "Quasi *-algebras and generalized inductive limits of C*-algebras" (Studia Math. 202 (2011), 165-190)