On Commutant Lifting with Finite Defect, II

✍ Scribed by Rodrigo Arocena; Tomas Ya. Azizov; Aad Dijksma; Stefania A.M. Marcantognini

• Book ID: 102972338
• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 852 KB
• Volume: 144
• Category: Article
• ISSN: 0022-1236
• DOI: 10.1006/jfan.1996.2992

✦ Synopsis

dedicated to heinz langer on the occasion of his 60th birthday

In the lifting theorem of B. Sz.-Nagy, C. Foias , and D. Sarason the intertwining operator A, the operator that is lifted, is a contraction from one Hilbert space to another. J. A. Ball and J. W. Helton showed that a kind of lifting theorem still holds if the negative spectral subspace of the operator I&A*A is finite dimensional. In this paper we prove that this result remains valid if the Hilbert spaces are replaced by spaces with an indefinite metric.