Unitary and Selfadjoint Operators in Krein Spaces

  • János Bognár
Part of the Ergebnisse der Mathematik und ihrer Grenzgebiete book series (MATHE2, volume 78)


The study of linear operators in Krein spaces begins with this chapter. Main topics include criteria for the continuity of isometric operators (Section 3) as well as basic properties and the location of spectra of unitary and selfadjoint operators (Sections 4–7). In Section 8 it is proved that every continuous linear operator of a Hilbert space has a unitary dilation in a Krein space. Theorems 3.5, 3.10, 5.1, 5.5, 6.1, 7.5, 8.6 and Lemma 4.7 can be mentioned as representative results.


Corn Assure Resid Proal 


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Copyright information

© Springer-Verlag Berlin Heidelberg 1974

Authors and Affiliations

  • János Bognár
    • 1
  1. 1.Mathematical Institute of the Hungarian Academy of SciencesBudapestHungary

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