Spectral decomposition of symmetric operator matrices

Mennicken, Reinhard and Shkalikov, Andrey A. (1996) Spectral decomposition of symmetric operator matrices. MATHEMATISCHE NACHRICHTEN, 179 (1). pp. 259-273. ISSN 0025-584X, 1522-2616

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Abstract

The authors study symmetric operator matrices L(o) = ((A)(B*) (B)(C)) in the product of Hilbert spaces H = H-1 x H-2, where the entries are not necessarily bounded operators. Under suitable assumptions the closure (L(o)) over bar exists and is a selfadjoint operator in H. With (L(o)) over bar, the closure of the transfer function M(lambda) = C - lambda -B*(A - lambda)B--1 is considered. Under the assumption that there exists a real number beta < inf rho(A) such that M(beta) much less than 0, it follows that beta is an element of rho((L(o)) over bar). Applying a factorization result of A.I. VIROZUB and V.I. MATSAEV [VM] to the holomorphic operator function M(lambda), the spectral subspaces of (L(o)) over bar corresponding to the intervals] - infinity, beta] and [beta, infinity[ and the restrictions of (L(o)) over bar to these subspaces are characterized. Similar results are proved for operator matrices T-o = ((A)(-B*) (B)(C)) which are symmetric in a Krein space.

Item Type: Article
Uncontrolled Keywords: FACTORIZATION; selfadjoint operator matrices; transfer functions; half range completeness; eigenfunction expansions for PDO
Subjects: 500 Science > 510 Mathematics
Divisions: Mathematics
Depositing User: Dr. Gernot Deinzer
Date Deposited: 15 Nov 2023 07:57
Last Modified: 15 Nov 2023 07:57
URI: https://pred.uni-regensburg.de/id/eprint/52105

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