Hyponormal powers of composition operators

Authors:
Phillip Dibrell and James T. Campbell

Journal:
Proc. Amer. Math. Soc. **102** (1988), 914-918

MSC:
Primary 47B38; Secondary 47B20

DOI:
https://doi.org/10.1090/S0002-9939-1988-0934867-X

MathSciNet review:
934867

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Abstract: Let , be measurable transformations which define bounded composition operators on of a -finite measure space. Denote their respective Radon-Nikodym derivatives by . The main result of this paper is that if , then for each of the positive integers the operator is hyponormal. As a consequence, we see that the sufficient condition established by Harrington and Whitley for hyponormality of a composition operator is actually sufficient for all powers to be hyponormal.

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DOI:
https://doi.org/10.1090/S0002-9939-1988-0934867-X

Article copyright:
© Copyright 1988
American Mathematical Society