Remarks on numerical ranges of operators in spaces with an indefinite metric

Li, Chi-Kwong; Rodman, Leiba

doi:10.1090/S0002-9939-98-04242-7

Remarks on numerical ranges of operators in spaces with an indefinite metric
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by Chi-Kwong Li and Leiba Rodman PDF

Proc. Amer. Math. Soc. 126 (1998), 973-982 Request permission

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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