On the approximation numbers and spectral eigenvalues
| Autor: | Imen Bhouri, Haı¨kel Skhiri |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Approximation numbers
Numerical Analysis Pure mathematics Algebra and Number Theory Essential spectral radius Spectral radius Fredholm operator Essential spectrum Mathematical analysis Spectrum (functional analysis) Hilbert space Algebraic multiplicity Normal matrix Bounded operator Orbits of conjugation symbols.namesake Fredholm Operator symbols Discrete Mathematics and Combinatorics Geometry and Topology Eigenvalues and eigenvectors Mathematics |
| Zdroj: | Linear Algebra and its Applications. 430:847-854 |
| ISSN: | 0024-3795 |
| DOI: | 10.1016/j.laa.2008.09.031 |
| Popis: | In the present paper, we characterize the approximation numbers orbits of conjugation of a bounded operator T in an Hilbert space and there relationship with the eigenvalues of T . As a consequence we obtain that for normal operators | λ n ( T ) | = inf { ρ ( T - L ) : TL = LT and dim R ( L ) n } , where λ n ( T ) is the n-th eigenvalue of T . We illustrate with an example that the equality doesn’t hold in general. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect