Journal article
Which 2-hyponormal 2-variable weighted shifts are subnormal?
Linear algebra and its applications, Vol.429(8-9), pp.2227-2238
10/16/2008
DOI: 10.1016/j.laa.2008.06.017
Abstract
It is well known that a 2-hyponormal unilateral weighted shift with two equal weights must be flat, and therefore subnormal. By contrast, a 2-hyponormal 2-variable weighted shift which is both horizontally flat and vertically flat need not be subnormal. In this paper we identify a large class S of flat 2-variable weighted shifts for which 2-hyponormality is equivalent to subnormality. One measure of the size of S is given by the fact that within S there are hyponormal shifts which are not subnormal.
Details
- Title: Subtitle
- Which 2-hyponormal 2-variable weighted shifts are subnormal?
- Creators
- Raúl E Curto - Department of Mathematics, The University of Iowa, Iowa City, IA 52242, United StatesSang Hoon Lee - Department of Mathematics, Chungnam National University, Daejeon 305-764, Republic of KoreaJasang Yoon - Department of Mathematics, Hanyang University, Seoul 133-791, Republic of Korea
- Resource Type
- Journal article
- Publication Details
- Linear algebra and its applications, Vol.429(8-9), pp.2227-2238
- DOI
- 10.1016/j.laa.2008.06.017
- ISSN
- 0024-3795
- eISSN
- 1873-1856
- Publisher
- Elsevier Inc
- Language
- English
- Date published
- 10/16/2008
- Academic Unit
- Mathematics
- Record Identifier
- 9983985883402771
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