A note on joint hyponormality

Authors:
Scott McCullough and Vern Paulsen

Journal:
Proc. Amer. Math. Soc. **107** (1989), 187-195

MSC:
Primary 47B20

DOI:
https://doi.org/10.1090/S0002-9939-1989-0972236-8

MathSciNet review:
972236

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Abstract: We describe certain cones of polynomials in two variables naturally associated to the class(es) of operators for which the tuple is jointly (weakly) hyponormal. As an application we give an example of an operator such that the tuple is jointly but not weakly hyponormal. Further, we show that there exists a polynomially hyponormal operator which is not subnormal if and only if there exists a weighted shift with the same property.

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Additional Information

DOI:
https://doi.org/10.1090/S0002-9939-1989-0972236-8

Keywords:
Jointly hyponormal

Article copyright:
© Copyright 1989
American Mathematical Society