A boundary value problem with a discontinuous coefficient and containing a spectral parameter in the boundary condition.
A characterization for the spectral capacity of a finite system of operators
A characterization of exponential stability for periodic evolution families in terms of lower semicontinuous functionals.
A characterization of some subsets of S-essential spectra of a multivalued linear operator
We characterize some S-essential spectra of a closed linear relation in terms of certain linear relations of semi-Fredholm type.
A characterization of the essential spectrum and applications
In this article the essential spectrum of closed, densely defined linear operators is characterized on a large class of spaces, which possess the Dunford-Pettis property or which isomorphic to one of the spaces . A practical...
A Class of Contractions in Hilbert Space and Applications
We characterize the bounded linear operators T in Hilbert space which satisfy T = βI + (1-β)S where β ∈ (0,1) and S is a contraction. The characterizations include a quadratic form inequality, and a domination condition of the discrete semigroup by the continuous semigroup . Moreover, we give a stronger quadratic form inequality which ensures that . The results apply to large classes of Markov operators on countable spaces or on locally compact groups.
A connection between spectral radius and trace
A formula for the eigenvalues of a compact operator
A formula for the inner spectral radius.
A formula to calculate the spectral radius of a compact linear operator.
A Fredholm Determinant Theory for p-Summing Maps in Banach Spaces.
A Generalization of the Stein-Rosenberg Theorem to Banach Spaces.
A generalization of the uniform ergodic theorem to poles of arbitrary order
A la recherche du spectre perdu: An invitation to nonlinear spectral theory
We give a survey on spectra for various classes of nonlinear operators, with a particular emphasis on a comparison of their advantages and drawbacks. Here the most useful spectra are the asymptotic spectrum by M. Furi, M. Martelli and A. Vignoli (1978), the global spectrum by W. Feng (1997), and the local spectrum (called “phantom”) by P. Santucci and M. Väth (2000). In the last part we discuss these spectra for homogeneous operators (of any degree), and derive a discreteness result and a nonlinear...
A new approach to inverse spectral theory. II: General real potentials and the connection to the spectral measure.
A Note on Eigenvalue Problems with Eigenvalue Parameter in the Boundary Conditions.
A note on preservation of spectra for two given operators
We study the relationships between the spectra derived from Fredholm theory corresponding to two given bounded linear operators acting on the same space. The main goal of this paper is to obtain sufficient conditions for which the spectra derived from Fredholm theory and other parts of the spectra corresponding to two given operators are preserved. As an application of our results, we give conditions for which the above mentioned spectra corresponding to two multiplication operators acting on the...
A note on semicharacters
A note on spectra of weighted composition operators on weighted Banach spaces of holomorphic functions.
A note on the -Browder’s and -Weyl’s theorems
Let be a Banach space operator. In this paper we characterize -Browder’s theorem for by the localized single valued extension property. Also, we characterize -Weyl’s theorem under the condition where is the set of all eigenvalues of which are isolated in the approximate point spectrum and is the set of all left poles of Some applications are also given.