Abstract
This paper describes the spectrum and the upper and lower Fredholm spectra of (n + m)-tuples (F(A1),., F(An), G(B1),., G(Bm)) of operators, where (Ai) and (Bj) are systems of operators in two Hilbert spaces H1 and H2, and F and G are certain linear operators defined on L(Hi). Using spectral mapping theorems the spectra of operators constructed by the action of a polynomial on a system (F(A1),., F(An), G(B1),., G(Bm)) is obtained. In particular, the spectra of the elementary operator and tensor products of operators is determined.
Original language | English |
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Pages (from-to) | 426-432 |
Number of pages | 7 |
Journal | Proceedings of the American Mathematical Society |
Volume | 91 |
Issue number | 3 |
DOIs | |
State | Published - Jul 1984 |
Externally published | Yes |
Keywords
- Elementary operator
- Essential spectrum
- Fredholm operator
- Joint spectrum
- Spectral mapping theorem
- Spectrum
- Tensor products
- Upper and lower Fredholm spectra