Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4592357 | Journal of Functional Analysis | 2007 | 18 Pages |
Abstract
In this paper, we introduce a new kind of spectrum for the C⋅0-class contractions. Since elements in this spectrum are functions, rather than numbers, we shall call it functional spectrum. Functional spectrum is a “large” closed subset of the Hardy space over the unit disk, and in many cases there is a canonical embedding of classical spectrum into functional spectrum. The study is carried out in the setting of the Hardy space over the bidisk H2(D2), on which every C⋅0-class contraction has a representation. A key tool is reduction operator. The reduction operator also gives rise to an equivalent statement of the Invariant Subspace Problem.
Related Topics
Physical Sciences and Engineering
Mathematics
Algebra and Number Theory