Author(s) :
Peter Jonas
Preprint series of the Institute of Mathematics, Technische Universität Berlin
Preprint 03-2003
MSC 2000
- 47B50 Operators on spaces with an indefinite metric
-
47A56 Functions whose values are linear operators
-
47A60 Functional calculus
Abstract :
For selfadjoint operators in Krein spaces the
notions of spectral points of positive and negative type are
basic in the spectral and perturbation theory of these operators.
The aim of this paper is to give different characterizations
of these sign types of spectral points. Moreover a local variant
of definitizability is characterized in various ways.
Keywords :
selfadjoint and unitary operators in Krein spaces, spectral points of positive and negative type, spectral function, definitizable operators, selfadjoint linear relations