Quasitriangular plus small compact = strongly irreducible

Authors
Citation
Yq. Ji, Quasitriangular plus small compact = strongly irreducible, T AM MATH S, 351(11), 1999, pp. 4657-4673
Citations number
11
Categorie Soggetti
Mathematics
Journal title
TRANSACTIONS OF THE AMERICAN MATHEMATICAL SOCIETY
ISSN journal
00029947 → ACNP
Volume
351
Issue
11
Year of publication
1999
Pages
4657 - 4673
Database
ISI
SICI code
0002-9947(199911)351:11<4657:QPSC=S>2.0.ZU;2-8
Abstract
Let T be a bounded linear operator acting on a separable infinite dimension al Hilbert space. Let epsilon be a positive number. In this article, we pro ve that the perturbation of T by a compact operator K with parallel to K pa rallel to < epsilon can be strongly irreducible if T is a quasitriangular o perator with the spectrum sigma(T) connected. The Main Theorem of this arti cle nearly answers the question below posed by D. A. Herrero. Suppose that T is a bounded linear operator acting on a separable infinite dimensional Hilbert space with sigma(T) connected. Let epsilon > 0 be given . Is there a compact operator K with parallel to K parallel to < epsilon su ch that T + K is strongly irreducible?