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Finite operators and similarity orbits


Authors: Lawrence A. Fialkow and Domingo A. Herrero
Journal: Proc. Amer. Math. Soc. 93 (1985), 601-609
MSC: Primary 47A66; Secondary 47A12, 47A65
DOI: https://doi.org/10.1090/S0002-9939-1985-0776187-X
MathSciNet review: 776187
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Abstract: In this note we answer the question of J. P. Williams as to which Hilbert space operators $ T$ have the property that every similarity transformation $ {W^{ - 1}}TW$ is a finite operator: $ T$ has this property if and only if its image in the Calkin algebra satisfies a quadratic equation.


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DOI: https://doi.org/10.1090/S0002-9939-1985-0776187-X
Article copyright: © Copyright 1985 American Mathematical Society

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