Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9502696 | Journal of Mathematical Analysis and Applications | 2005 | 12 Pages |
Abstract
A Hilbert space operator TâB(H) is hereditarily normaloid (notation: TâHN) if every part of T is normaloid. An operator TâHN is totally hereditarily normaloid (notation: TâTHN) if every invertible part of T is normaloid. We prove that THN-operators with Bishop's property (β), also THN-contractions with a compact defect operator such that Tâ1(0)âTââ1(0) and non-zero isolated eigenvalues of T are normal, are not supercyclic. Take A and B in THN and let dAB denote either of the elementary operators in B(B(H)): ÎAB and δAB, where ÎAB(X)=AXBâX and δAB(X)=AXâXB. We prove that if non-zero isolated eigenvalues of A and B are normal and Bâ1(0)âBââ1(0), then dAB is an isoloid operator such that the quasi-nilpotent part H0(dABâλ) of dABâλ equals (dABâλ)â1(0) for every complex number λ which is isolated in Ï(dAB). If, additionally, dAB has the single-valued extension property at all points not in the Weyl spectrum of dAB, then dAB, and the conjugate operator dABâ, satisfy Weyl's theorem.
Keywords
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Physical Sciences and Engineering
Mathematics
Analysis
Authors
B.P. Duggal, C.S. Kubrusly,