Krein space, definitizable operator, critical point
We give an example of a positive operator B in a Krein space with the following properties: the nonzero spectrum of B consists of isolated simple eigenvalues, the norms of the orthogonal spectral projections in the Krein space onto the eigenspaces of B are uniformly bounded and the point ∞ is a singular critical point of B.
Proceedings of the American Mathematical Society
Required Publisher's Statement
First published in "Proceedings of the American Mathematical Society" in 2000, published by the American Mathematical Society.
Ćurgus, Branko; Gheondea, Aurelian; and Langer, Heinz, "On Singular Critical Points of Positive Operators in Krein Spaces" (2000). Mathematics. 8.