Finite Blaschke products of contractions
| dc.citation.epage | 370 | en_US |
| dc.citation.issue | en_US | |
| dc.citation.spage | 359 | en_US |
| dc.citation.volume | 368 | en_US |
| dc.citation.woscount | 4 | |
| dc.contributor.author | Gau, HL | en_US |
| dc.contributor.author | Wu, PY | en_US |
| dc.contributor.department | 應用數學系 | zh_TW |
| dc.contributor.department | Department of Applied Mathematics | en_US |
| dc.date.accessioned | 2014-12-08T15:40:38Z | |
| dc.date.available | 2014-12-08T15:40:38Z | |
| dc.date.issued | 2003-07-15 | en_US |
| dc.description.abstract | Let A be a contraction on Hilbert space H and phi a finite Blaschke product. In this paper, we consider the problem when the norm of phi(A) is equal to 1. We show that (1) parallel tophi(A)parallel to = 1 if and only if parallel toA(k)parallel to = 1, where k is the number of zeros of phi counting multiplicity, and (2) if H is finite-dimensional and A has no eigenvalue of modulus 1, then the largest integer I for which parallel toA(l)parallel to = 1 is at least m/(n - m), where n = dim H and m = dim ker(I - A*A), and, moreover, l = n - 1 if and only if m = n - 1. (C) 2003 Elsevier Science Inc. All rights reserved. | en_US |
| dc.identifier.doi | 10.1016/S0024-3795(02)00697-3 | en_US |
| dc.identifier.issn | 0024-3795 | en_US |
| dc.identifier.journal | LINEAR ALGEBRA AND ITS APPLICATIONS | en_US |
| dc.identifier.uri | http://dx.doi.org/10.1016/S0024-3795(02)00697-3 | en_US |
| dc.identifier.uri | https://ir.lib.nycu.edu.tw/handle/11536/27712 | |
| dc.identifier.wosnumber | WOS:000183665000023 | |
| dc.language.iso | en_US | en_US |
| dc.subject | contraction | en_US |
| dc.subject | Blaschke product | en_US |
| dc.subject | compression of the shift | en_US |
| dc.subject | Toeplitz operator | en_US |
| dc.subject | Hankel operator | en_US |
| dc.title | Finite Blaschke products of contractions | en_US |
| dc.type | Article | en_US |