Remarks on numerical ranges of operators

in spaces with an indefinite metric

Authors:
Chi-Kwong Li and Leiba Rodman

Journal:
Proc. Amer. Math. Soc. **126** (1998), 973-982

MSC (1991):
Primary 15A60, 47A12, 47A37

MathSciNet review:
1443838

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Abstract | References | Similar Articles | Additional Information

Abstract: The numerical range of an operator on an indefinite inner product space (possibly infinite dimensional) is studied. In particular, operators having bounded numerical ranges are characterized, and the angle points of the numerical range and their connections with eigenvalues are described.

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Additional Information

**Chi-Kwong Li**

Affiliation:
Department of Mathematics, The College of William and Mary, Williamsburg, Virginia 23187

Email:
ckli@math.wm.edu

**Leiba Rodman**

Affiliation:
Department of Mathematics, The College of William and Mary, Williamsburg, Virginia 23187

Email:
lxrodm@math.wm.edu

DOI:
https://doi.org/10.1090/S0002-9939-98-04242-7

Keywords:
Numerical range,
indefinite scalar product,
Krein space.

Received by editor(s):
September 23, 1996

Additional Notes:
Research of both authors was partially supported by NSF Grants.

Communicated by:
Palle E. T. Jorgensen

Article copyright:
© Copyright 1998
American Mathematical Society