Abstract
It is shown that if A is a compact operator on a Hilbert space with its numerical range W(A) contained in the closed unit disc double-struck D sign̄ and with W(A) intersecting the unit circle at infinitely many points, then W(A) is equal to double-struck D sign̄. This is an infinite-dimensional analogue of a result of Anderson for finite matrices.
Original language | English |
---|---|
Pages (from-to) | 3159-3162 |
Number of pages | 4 |
Journal | Proceedings of the American Mathematical Society |
Volume | 134 |
Issue number | 11 |
DOIs | |
State | Published - Nov 2006 |
Keywords
- Compact operator
- Numerical range