Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4617275 | Journal of Mathematical Analysis and Applications | 2012 | 16 Pages |
Abstract
A new method of verifying the subnormality of unbounded Hilbert space operators based on an approximation technique is proposed. Diverse sufficient conditions for subnormality of unbounded weighted shifts on directed trees are established. An approach to this issue via consistent systems of probability measures is invented. The role played by determinate Stieltjes moment sequences is elucidated. Lambert's characterization of subnormality of bounded operators is shown to be valid for unbounded weighted shifts on directed trees that have sufficiently many quasi-analytic vectors, which is a new phenomenon in this area.
Related Topics
Physical Sciences and Engineering
Mathematics
Analysis
Authors
Piotr BudzyÅski, Zenon Jan JabÅoÅski, Il Bong Jung, Jan Stochel,