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We produce a variety of odd bounded Fredholm modules and odd spectral triples on Cuntz-Krieger algebras by means of realizing these algebras as "the algebra of functions on a non-commutative space" coming from a sub shift of finite type. We…

K-Theory and Homology · Mathematics 2015-03-02 Magnus Goffeng , Bram Mesland

We present a definition of indefinite Kasparov modules, a generalisation of unbounded Kasparov modules modelling non-symmetric and non-elliptic (e.g. hyperbolic) operators. Our main theorem shows that to each indefinite Kasparov module we…

K-Theory and Homology · Mathematics 2016-02-16 Koen van den Dungen , Adam Rennie

By considering the general properties of approximate units in differentiable algebras, we are able to present a unified approach to characterising completeness of spectral metric spaces, existence of connections on modules, and the lifting…

Operator Algebras · Mathematics 2016-10-24 Bram Mesland , Adam Rennie

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

We improve our previous results on indefinite Kasparov modules, which provide a generalisation of unbounded Kasparov modules modelling non-symmetric and non-elliptic (e.g. hyperbolic) operators. In particular, we can weaken the assumptions…

K-Theory and Homology · Mathematics 2019-10-03 Koen van den Dungen

This paper extends the notion of a spectral triple to a relative spectral triple, an unbounded analogue of a relative Fredholm module for an ideal $J\triangleleft A$. Examples include manifolds with boundary, manifolds with conical…

K-Theory and Homology · Mathematics 2019-11-28 Iain Forsyth , Magnus Goffeng , Bram Mesland , Adam Rennie

In this paper we investigate the unbounded Kasparov product between a differentiable module and an unbounded cycle of a very general kind that includes all unbounded Kasparov modules and hence also all spectral triples. Our assumptions on…

K-Theory and Homology · Mathematics 2019-08-21 Jens Kaad

In noncommutative geometry one is interested in invariants such as the Fredholm index or spectral flow and their calculation using cyclic cocycles. A variety of formulae have been established under side conditions called summability…

Operator Algebras · Mathematics 2009-12-16 Denis Potapov , Fyodor Sukochev

In this paper we introduce the curvature of densely defined universal connections on Hilbert $C^{*}$-modules relative to a spectral triple (or unbounded Kasparov module), obtaining a well-defined curvature operator. Fixing the spectral…

Operator Algebras · Mathematics 2019-11-13 Bram Mesland , Adam Rennie , Walter D. van Suijlekom

We prove some general Sobolev-type and related inequalities for positive operators A of given ultracontractive spectral decay, without assuming e^{-tA} is submarkovian. These inequalities hold on functions, or pure states, as usual, but…

Functional Analysis · Mathematics 2011-02-11 Michel Rumin

In the setting of non-type $\ty{II_1}$ representations, we propose a definition of {\it deformed Fredholm module} $\big[D_\ct|D_\ct|^{-1}\,,\,{\bf\cdot}\,\big]_\ct$ for a modular spectral triple $\ct$, where $D_\ct$ is the deformed Dirac…

Operator Algebras · Mathematics 2022-09-14 Fabio Ciolli , Francesco Fidaleo

We extend unbounded Kasparov theory to encompass conformal group and quantum group equivariance. This new framework allows us to treat conformal actions on both manifolds and noncommutative spaces. As examples, we present unbounded…

Operator Algebras · Mathematics 2026-02-24 Ada Masters , Adam Rennie

We explicitly construct Fredholm modules and spectral triples representing any element of $K$-homology groups of Hensel-Steinitz algebras.

Operator Algebras · Mathematics 2025-10-09 Shelley Hebert , Slawomir Klimek , Matt McBride

In this paper, we enlarge the space of uniformly supported pseudo-differential operators on some groupoids by considering kernels satisfying certain asymptotic estimates. We show that such enlarged space contains the compact parametrix, and…

Analysis of PDEs · Mathematics 2013-02-28 Bing Kwan So

This survey deals with the construction of a category of spectral triples that is compatible with the Kasparov product in $KK$-theory. These notes serve as an intuitive guide to these results, avoiding the necessary technical proofs. We…

K-Theory and Homology · Mathematics 2013-04-16 Bram Mesland

We provide Fredholm conditions for compatible differential operators on certain Lie manifolds (that is, on certain possibly non-compact manifolds with nice ends). We discuss in more detail the case of manifolds with cylindrical, hyperbolic,…

Analysis of PDEs · Mathematics 2023-08-14 Ivan Beschastnyi , Catarina Carvalho , Victor Nistor , Yu Qiao

We study unbounded invariant and covariant derivations on the quantum disk. In particular we answer the question whether such derivations come from operators with compact parametrices and thus can be used to define spectral triples.

Operator Algebras · Mathematics 2017-09-26 Slawomir Klimek , Matt McBride , Sumedha Rathnayake , Kaoru Sakai , Honglin Wang

We give a construction allowing to lift spectral triples to crossed products by Hilbert bimodules. The spectral triple one obtains is a concrete unbounded representative of the Kasparov product of the spectral triple and the…

Operator Algebras · Mathematics 2013-10-23 Olivier Gabriel , Martin Grensing

This paper is a follow-up to a recent article about the essential spectrum of Toeplitz operators acting on the Bergman space over the unit ball. As mentioned in the said article, some of the arguments can be carried over to the case of…

Functional Analysis · Mathematics 2018-04-12 Raffael Hagger

In this paper the concept of unbounded Fredholm operators on Hilbert C*- modules over an arbitrary C*-algebra is discussed and the Atkinson theorem is generalized for bounded and unbounded Feredholm operators on Hilbert C*-modules over…

Operator Algebras · Mathematics 2015-06-26 Assadollah Niknam , Kamran Sharifi
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