Journal article
Propagation phenomena for hyponormal 2-variable weighted shifts
Journal of operator theory, Vol.58(1), pp.175-203
06/01/2007
Abstract
We study the class of hyponormal 2-variable weighted shifts with two consecutive equal weights in the weight sequence of one of the coordinate operators. We show that under natural assumptions on the coordinate operators, the presence of consecutive equal weights leads to horizontal or vertical flatness, in a way that resembles the situation for 1-variable weighted shifts. In I-variable, it is well known that flat weighted shifts are necessarily subnormal (with finitely atomic Berger measures). By contrast, we exhibit a large collection of flat (i.e., horizontally and vertically flat) 2-variable weighted shifts which are hyponormal but not subnormal. Moreover, we completely characterize the hyponormality and subnormality of symmetrically flat contractive 2-variable weighted shifts.
Details
- Title: Subtitle
- Propagation phenomena for hyponormal 2-variable weighted shifts
- Creators
- Raul E CurtoJasang Yoon
- Resource Type
- Journal article
- Publication Details
- Journal of operator theory, Vol.58(1), pp.175-203
- Publisher
- THETA FOUNDATION
- ISSN
- 0379-4024
- eISSN
- 1841-7744
- Number of pages
- 29
- Language
- English
- Date published
- 06/01/2007
- Academic Unit
- Mathematics
- Record Identifier
- 9984241055902771
Metrics
2 Record Views