Arkiv för Matematik
- Ark. Mat.
- Volume 38, Number 1 (2000), 97-110.
Indices, characteristic numbers and essential commutants of Toeplitz operators
Abstract
For an essentially normal operator T, it is shown that there exists a unilateral shift of multiplicity m in C*(T) if and only if γ(T)≠0 and γ(T)/m. As application, we prove that the essential commutant of a unilateral shift and that of a bilateral shift are not isomorphic as C*-algebras. Finally, we construct a natural C*-algebra ε + ε* on the Bergman space L ${}_{a}^{2}$ (Bn), and show that its essential commutant is generated by Toeplitz operators with symmetric continuous symbols and all compact operators.
Note
Supported by NSFC and Laboratory of Mathematics for Nonlinear Science at Fudan University.
Article information
Source
Ark. Mat., Volume 38, Number 1 (2000), 97-110.
Dates
Received: 30 June 1998
Revised: 15 December 1998
First available in Project Euclid: 31 January 2017
Permanent link to this document
https://projecteuclid.org/euclid.afm/1485898669
Digital Object Identifier
doi:10.1007/BF02384493
Mathematical Reviews number (MathSciNet)
MR1749361
Zentralblatt MATH identifier
1021.47018
Rights
2000 © Institut Mittag-Leffer
Citation
Guo, Kunyu. Indices, characteristic numbers and essential commutants of Toeplitz operators. Ark. Mat. 38 (2000), no. 1, 97--110. doi:10.1007/BF02384493. https://projecteuclid.org/euclid.afm/1485898669