1. Institut Girard Desargues, UFR de Mathématiques, Université Lyon 1, 69622, Villeurbanne Cedex, France 2. School of Mathematics, University of Leeds, Leeds, LS2 9JT, U.K.
Abstract:
We provide a characterization of J-class and Jmix-class unilateral weighted shifts on in terms of their weight sequences. In contrast to the previously mentioned result we show that a bilateral weighted shift on cannot be a J-class operator. During this research the second author was fully supported by SFB 701 “Spektrale Strukturen und Topologische Methoden in der Mathematik" at the University of Bielefeld, Germany. He would also like to express his gratitude to Professor H. Abels for his support.