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Complex Chern-Simons bundles are line bundles with connection, originating in the study of quantization of moduli spaces of flat connections with complex gauge groups. In this paper we introduce and study these bundles in the families…

Algebraic Geometry · Mathematics 2022-03-17 Dennis Eriksson , Gerard Freixas i Montplet , Richard A. Wentworth

We construct a Hochschild-Kostant-Rosenberg-type quasi-isomorphism for the negative cyclic homology of the category of global matrix factorizations on a smooth separated scheme of finite type over a field. The map is explicit enough to…

Algebraic Geometry · Mathematics 2021-09-30 Kuerak Chung , Bumsig Kim , Taejung Kim

We present the solution of a longstanding internal problem of noncommutative geometry, namely the computation of the index of a transversally elliptic operator on an arbitrary foliation. The new and crucial ingredient is a certain Hopf…

Differential Geometry · Mathematics 2009-10-31 Alain Connes , Henri Moscovici

We introduce a homology theory for k-graphs and explore its fundamental properties. We establish connections with algebraic topology by showing that the homology of a k-graph coincides with the homology of its topological realisation as…

Operator Algebras · Mathematics 2011-10-10 Alex Kumjian , David Pask , Aidan Sims

We compute the Hochschild, cyclic, and periodic cyclic homology groups of algebras of families of Laurent complete symbols on manifolds with corners. We show in particular that the spectral sequence associated with Hochschild homology…

K-Theory and Homology · Mathematics 2007-05-23 Moulay Benameur , Victor Nistor

We prove a cyclic cohomological analogue of Haefliger's van Est-type theorem for the groupoid of germs of diffeomorphisms of a manifold. The differentiable version of cyclic cohomology is associated to the algebra of transverse differential…

Differential Geometry · Mathematics 2007-05-23 Alain Connes , Henri Moscovici

We describe several applications of the theory of cycles to questions in Commutative Algebra. The main topic is the use of the theory of local Chern characters to answer some questions on modules of finite homological dimension. This paper…

Commutative Algebra · Mathematics 2007-05-23 Paul C. Roberts

We consider a class of C*-algebras associated to one parameter continuous tensor product systems of Hilbert modules, which can be viewed as continuous counterparts of Pimsner's Toeplitz algebras. By exhibiting a homotopy of…

Operator Algebras · Mathematics 2007-05-23 Ilan Hirshberg

We consider the assembly map for principal bundles with fiber a countable discrete group. We obtain an index-theoretic interpretation of this homomorphism by providing a tensor-product presentation for the module of sections associated to…

K-Theory and Homology · Mathematics 2022-11-02 Jens Kaad , Valerio Proietti

For every Hecke C*-algebra of right-angled, hyperbolic type, we construct a smooth subalgebra to which traces associated with arbitrary conjugacy classes in the associated Coxeter group extend. We calculate the pairing with K-theory of the…

Operator Algebras · Mathematics 2026-03-25 Piotr Nowak , Sanaz Pooya , Sven Raum , Adam Skalski

Following the idea of Galois-type extensions and entwining structures, we define the notion of a principal extension of noncommutative algebras. We show that modules associated to such extensions via finite-dimensional corepresentations are…

K-Theory and Homology · Mathematics 2007-05-23 Tomasz Brzezinski , Piotr M. Hajac

We study twisted $Spin^c$-manifolds over a paracompact Hausdorff space $X$ with a twisting $\alpha: X \to K(\ZZ, 3)$. We introduce the topological index and the analytical index on the bordism group of $\alpha$-twisted $Spin^c$-manifolds…

K-Theory and Homology · Mathematics 2008-07-09 Bai-Ling Wang

We prove a super-version of Nest-Tsygan's algebraic index theorem. This work is inspired by the appearance of the same cobordism invariants in three related stories: index theory, trace methods in the deformation theory of algebras, and…

Quantum Algebra · Mathematics 2023-09-12 Araminta Amabel

Local Hochschild, cyclic Homology and K-theory were introduced by N. Teleman in [10] with the purpose of unifying different settings of the index theorem. This paper is one of the research topics announced in [10], {\S}10. The definition of…

K-Theory and Homology · Mathematics 2012-06-12 Nicolae Teleman

In earlier joint work with A. Connes on transverse index theory on foliations, cyclic cohomology adapted to Hopf algebras has emerged as a decisive tool in deciphering the total index class of the hypoelliptic signature operator. We have…

Differential Geometry · Mathematics 2015-02-10 Henri Moscovici

To each algebra over the complex numbers we associate a sequence of abelian groups in a contravariant functorial way. In degree (m-1) we have the m-summable Fredholm modules over the algebra modulo stable m-summable perturbations. These new…

K-Theory and Homology · Mathematics 2010-02-02 Jens Kaad

For a compact space X we consider extending endomorphisms of the algebra C(X) to be endomorphisms of Arens-Hoffman and Cole extensions of C(X). Given a non-linear, monic polynomial p in C(X)[t], with C(X)[t]/pC(X)[t] semi-simple, we show…

Functional Analysis · Mathematics 2007-05-23 J. F. Feinstein , T. J. Oliver

The Chern-Galois theory is developed for corings or coalgebras over non-commutative rings. As the first step the notion of an entwined extension as an extension of algebras within a bijective entwining structure over a non-commutative ring…

Rings and Algebras · Mathematics 2008-11-01 Gabriella Böhm , Tomasz Brzezinski

Let $G = GL(n)$ and $K = GL(p) \times GL(q)$ with $p+q=n$, where the groups are taken over $\C$. In this paper we study a certain family of $K$-orbit closures on the flag variety $X$ of $G$. The geometry of these orbit closures plays a…

Algebraic Geometry · Mathematics 2026-03-31 William Graham , Minyoung Jeon , Scott Joseph Larson

This paper expresses the Chern character for topological K-theory based on the formulation of the family of Fredholm operators, by using the points at which the Fredholm operator becomes singular (Fermi points). In particular, we explain…

K-Theory and Homology · Mathematics 2026-03-11 Kyouhei Horie