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Level sets of (p, e- p) outer generalized pseudo spectrum
D. Sukumar,
Published in Springer Science and Business Media B.V.
2020
Volume: 28
   
Issue: 1
Pages: 57 - 70
Abstract
Let A be a complex Banach algebra with unit e. Let p be a non trivial idempotent element in A and ε> 0. For a∈ A, it is proved that the interior of the level set of (p, e- p) - ε pseudo spectrum of a is empty in the unbounded component of (p, e- p) resolvent set of a. An example is constructed to show that the condition ‘unbounded component’ can not be dropped. Further, it is proved this ‘unbounded component’ can be dropped in the case when A is B(X) where X is a complex uniformly convex Banach space. That is, if T∈ B(X) then interior of the level set of (p, I- p) - ε pseudo spectrum is empty in (p, I- p) resolvent set of T. © 2017, Forum D'Analystes, Chennai.
About the journal
JournalData powered by TypesetJournal of Analysis
PublisherData powered by TypesetSpringer Science and Business Media B.V.
ISSN09713611