|
|||||
|
|
Separating classes of composition operators via subnormal condition |
|
| Authors: | Il Bong Jung Mi Ryeong Lee Sang Soo Park |
| Affiliation: | Department of Mathematics, College of Natural Sciences, Kyungpook National University, Daegu 702-702 Korea ; Department of Mathematics, College of Natural Sciences, Kyungpook National University, Daegu 702-702 Korea ; Institute of Mathematical Science, Ewha Womans University, Seoul, 120-750, Korea |
| Abstract: | Several classes have been considered to study the weak subnormalities of Hilbert space operators. One of them is  -hypnormality, which comes from the Bram-Halmos criterion for subnormal operators. In this note we consider  -hyponormality, which is the parallel version corresponding to the Embry characterization for subnormal operators. We characterize  -hyponormality of composition operators via  -th Radon-Nikodym derivatives and present some examples to distinguish the classes. |
| Keywords: | Composition operator subnormal operator. |
| 点击此处可从《Proceedings of the American Mathematical Society》浏览原始摘要信息 | |
| 点击此处可从《Proceedings of the American Mathematical Society》下载全文 | |