### The numerical range of non-negative operators in Krein spaces

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 $W(A)\cap W_{\rm co}(A)$.

Published in: Linear algebra and its applications, 438(2013), 5, Seite 2542-2556 Philipp, Friedrich (Author) Article English 2013 0024-3795 Show QR Code

 Published in: Linear algebra and its applications, 438(2013), 5, Seite 2542-2556
Feedback Delivery Service Interlibrary Loan