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19982004
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math.FA2004

The uniqueness of the spectral flow on spaces of unbounded self--adjoint Fredholm operators

Matthias Lesch

We discuss several natural metrics on spaces of unbounded self--adjoint operators and their relations, among them the Riesz and the graph metric. We show that the topologies of the…

math.FA2001

Unbounded Fredholm Operators and Spectral Flow

Bernhelm Booss-Bavnbek, Matthias Lesch, John Phillips

We study the gap (= "projection norm" = "graph distance") topology of the space of (not necessarily bounded) self--adjoint Fredholm operators in a separable Hilbert space by the Ca…

math.FA2000

On the number of square integrable solutions and self-adjointness of symmetric first order systems of differential equations

Matthias Lesch, Mark M. Malamud

The main purpose of this paper is to investigate the formal deficiency indices of a symmetric first order system on an interval , wh…

math.FA1999

On boundary value problems for Dirac type operators. I. Regularity and self-adjointness

Jochen Brüning, Matthias Lesch

In a series of papers, we will develop systematically the basic spectral theory of (self-adjoint) boundary value problems for operators of Dirac type. We begin in this paper with t…

math.FA1998

Traces on algebras of parameter dependent pseudodifferential operators and the eta-invariant

Matthias Lesch, Markus J. Pflaum

We identify Melrose's suspended algebra of pseudodifferential operators with a subalgebra of the algebra of parametric pseudodifferential operators with parameter space . For a…