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Related papers: Unbounded Fredholm Operators and Spectral Flow

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We describe two topologies on the space of unbounded Fredholm operators and we explain their K-theoretic relevance. In the process we also prove a very general result concerning the continuity of families of first order, elliptic boundary…

Differential Geometry · Mathematics 2007-05-23 Liviu I. Nicolaescu

Operators conserving the indefinite scalar product on a Krein space $(K,J)$ are called $J$-unitary. Such an operator $T$ is defined to be $S^1$-Fredholm if $T-z$ is Fredholm for all $z$ on the unit circle $S^1$, and essentially $S^1$-gapped…

Mathematical Physics · Physics 2016-10-27 Hermann Schulz-Baldes

Using the notion of spectral flow, we suggest a simple approach to various asymptotic problems involving eigenvalues in the gaps of the essential spectrum of self-adjoint operators. Our approach uses some elements of the spectral shift…

Spectral Theory · Mathematics 2015-05-13 Alexander Pushnitski

In this paper we begin a study of the space of unbounded self-adjoint Fredholm operators as a classifying space for K^{1}(X), with the goal of incorporating the information in the eigenspaces and eigenvalues of the operators. In particular,…

K-Theory and Homology · Mathematics 2008-05-31 Ronald G. Douglas , Jerome Kaminker

Let $\{A(t)\}_{t \in \mathbb{R}}$ be a path of self-adjoint Fredholm operators in a Hilbert space $\mathcal{H}$, joining endpoints $A_\pm$ as $t \to \pm \infty$. Computing the index of the operator $D_A= (d/d t) + A$ acting in…

Spectral Theory · Mathematics 2015-09-08 Alan Carey , Fritz Gesztesy , Galina Levitina , Fedor Sukochev

We study bounded operators defined in terms of the regular representations of the $C^*$-algebra of an amenable, Hausdorff, second countable locally compact groupoid endowed with a continuous $2$-cocycle. We concentrate on spectral…

Operator Algebras · Mathematics 2018-12-13 Marius Mantoiu , Victor Nistor

We relate the spectral flow to the index for paths of selfadjoint Breuer-Fredholm operators affiliated to a semifinite von Neumann algebra, generalizing results of Robbin-Salamon and Pushnitski. Then we prove the vanishing of the von…

Differential Geometry · Mathematics 2011-04-28 Sara Azzali , Charlotte Wahl

In this article we give a comprehensive treatment of a `Clifford module flow' along paths in the skew-adjoint Fredholm operators on a real Hilbert space that takes values in KO${}_{*}(\mathbb{R})$ via the Clifford index of…

K-Theory and Homology · Mathematics 2020-07-01 Chris Bourne , Alan L. Carey , Matthias Lesch , Adam Rennie

One may trace the idea that spectral flow should be given as the integral of a one form back to the 1974 Vancouver ICM address of I.M. Singer. Our main theorem gives analytic formulae for the spectral flow along a norm differentiable path…

Functional Analysis · Mathematics 2009-12-16 Alan Carey , Denis Potapov , Fyodor Sukochev

In this paper we show the invariance of the Fredholm index of non-smooth pseudodifferential operators with coefficients in H\"older spaces. By means of this invariance we improve previous spectral invariance results for non-smooth…

Functional Analysis · Mathematics 2020-09-24 Helmut Abels , Christine Pfeuffer

We study infinite weighted graphs with view to \textquotedblleft limits at infinity,\textquotedblright or boundaries at infinity. Examples of such weighted graphs arise in infinite (in practice, that means \textquotedblleft…

Mathematical Physics · Physics 2015-05-13 Palle E. T. Jorgensen

In this paper spectral theorems for not necessarily continuous normal and self-adjoint random operators on a complex separable Hilbert space are proved.

Spectral Theory · Mathematics 2017-01-24 Pastorel Gaspar

We introduce a framework for implementing quantum operations as steady states of a subsystem in an extended Hilbert space. Each operation has a spectral criterion for reaching the steady state. This adds a `spectral switch' mechanism to the…

Quantum Physics · Physics 2026-03-27 Man Yin Cheung , Mona Berciu , Kyle Monkman

The aim of this article is to explore in all remaining aspects the spectral theory of locally normal operators. In a previous article we proved the spectral theorem in terms of locally spectral measures. Here we prove the spectral theorem…

Functional Analysis · Mathematics 2025-11-04 Aurelian Gheondea

The spectral flow is an integer-valued homotopy invariant for paths of selfadjoint Fredholm operators. Lesch as well as Pejsachowicz, Fitzpatrick and Ciriza independently showed that it is uniquely characterised by its elementary…

Functional Analysis · Mathematics 2026-03-27 Marek Izydorek , Joanna Janczewska , Maciej Starostka , Nils Waterstraat

We compute, in topological terms, the spectral flow of an arbitrary family of self-adjoint Dirac type operators with classical (local) boundary conditions on a compact Riemannian manifold with boundary under the assumption that the initial…

Analysis of PDEs · Mathematics 2012-10-08 M. I. Katsnelson , V. E. Nazaikinskii

By the help of power series f we can naturally construct another power series that has as coefficients the absolute values of the coefficients of f. Utilising these functions we prove some inequalities for the spectral radius of the bounded…

Functional Analysis · Mathematics 2013-02-13 S. S. Dragomir

Let $\CR$ be the set of all bounded linear operators between Hilbert spaces $\cH, \cK$. This paper is devoted to the study of the topological properties of $\CR$ if certain natural metrics are considered on it. We also define an action of…

Functional Analysis · Mathematics 2007-05-23 Gustavo Corach , Alejandra Maestripieri , Mostafa Mbekhta

We develop a new approach to the study of spectral asymmetry. Working with the operator $\operatorname{curl}:=*\mathrm{d}$ on a connected oriented closed Riemannian 3-manifold, we construct, by means of microlocal analysis, the asymmetry…

Differential Geometry · Mathematics 2026-01-23 Matteo Capoferri , Dmitri Vassiliev

We construct explicit generators of the K-theory and K-homology of the coordinate algebra of `functions' on quantum projective spaces. We also sketch a construction of unbounded Fredholm modules, that is to say Dirac-like operators and…

Quantum Algebra · Mathematics 2012-02-21 Francesco D'Andrea , Giovanni Landi