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arXiv · 1208.3094

The numerical range of non-negative operators in Krein spaces

Friedrich Philipp·Carsten Trunk
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Abstract

We define and characterize the Krein space numerical range $W(A)$ and the Krein space co-numerical range $W_{\rm co}(A)$ of a non-negative operator $A$ in a Krein space. It is shown that the non-zero spectrum of $A$ is contained in the closure of $W(A)\cap W_{\rm co}(A)$.

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Friedrich Philipp, Carsten Trunk. 2012-08-15. The numerical range of non-negative operators in Krein spaces. https://arxiv.org/abs/1208.3094

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