Abstract
Let T be an operator on a Hubert space. We show that the pair (T, T) can be perturbed to an invertible pair if and only if T is Fredholm of index zero. We also exhibit a large class of Fredholm n-tuples acting on a Banach space which cannot be perturbed by finite rank operators to invertible ones.
Original language | English |
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Pages (from-to) | 195-198 |
Number of pages | 4 |
Journal | Proceedings of the American Mathematical Society |
Volume | 122 |
Issue number | 1 |
DOIs | |
State | Published - Sep 1994 |
Keywords
- Compact perturbation
- Fredholm n-tuple
- Index zero