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Preservation of the Range
under Perturbations of an Operator

Authors: Branko Curgus and Branko Najman
Journal: Proc. Amer. Math. Soc. 125 (1997), 2627-2631
MSC (1991): Primary 47B50, 47B25; Secondary 46C20
MathSciNet review: 1389513
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Abstract: A sufficient condition for the stability of the range of a positive operator in a Hilbert space is given. As a consequence, we get a class of additive perturbations which preserve regularity of the critical point $0$ of a positive operator in a Krein space.

References [Enhancements On Off] (What's this?)

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Additional Information

Branko Curgus
Affiliation: Department of Mathematics, Western Washington University, Bellingham, Washington 98225

Branko Najman
Affiliation: Department of Mathematics, University of Zagreb, Bijenička 30, 10000 Zagreb, Croatia

Keywords: Operator range, Krein space, definitizable operator, critical point
Received by editor(s): October 2, 1995
Received by editor(s) in revised form: March 18, 1996
Additional Notes: Professor Najman died in August 1996.
Communicated by: Palle E. T. Jorgensen
Article copyright: © Copyright 1997 American Mathematical Society