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Essential spectra of quasisimilar-quasihyponormal operators

Journal of Inequalities and Applications volume 2006, Article number: 72641 (2006) Cite this article

Abstract

It is shown that if is an upper-triangular operator matrix acting on the Hilbert space and if denotes the essential spectrum, then the passage from to is accomplished by removing certain open subsets of from the former. Using this result we establish that quasisimilar-quasihyponormal operators have equal spectra and essential spectra.

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Authors and Affiliations

  1. Department of Mathematics, Changwon National University, Changwon, 641–773, Korea

    An-Hyun Kim

  2. Department of Mathematics, Seoul National University, Seoul, 151-742, Korea

    In Hyoun Kim

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  1. An-Hyun Kim
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  2. In Hyoun Kim
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Correspondence to An-Hyun Kim.

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Open Access This article is distributed under the terms of the Creative Commons Attribution 2.0 International License ( https://creativecommons.org/licenses/by/2.0 ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Kim, AH., Kim, I.H. Essential spectra of quasisimilar-quasihyponormal operators. J Inequal Appl 2006, 72641 (2006). https://doi.org/10.1155/JIA/2006/72641

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