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Using a global version of the equivariant Chern character, we describe the complexified twisted equivariant K-theory of a space with a compact Lie group action in terms of fixed-point data. We apply this to the case of a compact Lie group…

Algebraic Topology · Mathematics 2014-02-26 Daniel S. Freed , Michael J. Hopkins , Constantin Teleman

This is an expository paper which gives a proof of the Atiyah-Singer index theorem for Dirac operators, presenting the theorem as a computation of the K-homology of a point. This paper and its follow up ("K-homology and index theory II:…

Differential Geometry · Mathematics 2016-04-13 Paul Baum , Erik van Erp

This paper describes how to compute algorithmically certain twisted signature invariants of a knot $K$ using twisted Blanchfield forms. An illustration of the algorithm is implemented on $(2,q)$-torus knots. Additionally, using satellite…

Geometric Topology · Mathematics 2024-03-18 Maciej Borodzik , Anthony Conway , Wojciech Politarczyk

We study equivariant families of Dirac operators on the source fibers of a Lie groupoid with a closed space of units and equipped with an action of an auxiliary compact Lie group. We use the Getzler rescaling method to derive a fixed-point…

Differential Geometry · Mathematics 2024-07-23 Ahmad Reza Haj Saeedi Sadegh , Shiqi Liu , Yiannis Loizides , Jesus Sanchez

Twisted complex $K$-theory can be defined for a space $X$ equipped with a bundle of complex projective spaces, or, equivalently, with a bundle of C$^*$-algebras. Up to equivalence, the twisting corresponds to an element of $H^3(X;\Z)$. We…

K-Theory and Homology · Mathematics 2007-05-23 Michael Atiyah , Graeme Segal

We study twisted modules for (weak) quantum vertex algebras and we give a conceptual construction of (weak) quantum vertex algebras and their twisted modules. As an application we construct and classify irreducible twisted modules for a…

Quantum Algebra · Mathematics 2008-12-18 Haisheng Li , Shaobin Tan , Qing Wang

In this paper, we introduce an algebra structure denoted by InvDer algebra whose which we twist an algebra thanks to an invertible derivation, where its inverse is also a derivation. We define InvDer Lie algebras, InvDer associated…

Rings and Algebras · Mathematics 2023-06-30 Imed Basdouri , Esmael Peyghan , Mohamed Amin Sadraoui

In this article, we survey the recent constructions of cyclic cocycles on the Harish-Chandra Schwartz algebra of a connected real reductive Lie group $G$ and their applications to higher index theory for proper cocompact $G$-actions.

K-Theory and Homology · Mathematics 2023-09-07 Paolo Piazza , Xiang Tang

To a coarse structure we associate a Grothendieck topology which is determined by coarse covers. A coarse map between coarse spaces gives rise to a morphism of Grothendieck topologies. This way we define sheaves and sheaf cohomology on…

Algebraic Geometry · Mathematics 2022-03-24 Elisa Hartmann

This article is concerned with the analysis of Dirac operators $D$ twisted by ramified Euclidean line bundles $(Z,\mathfrak{l})$-motivated by their relation with harmonic $\mathbf{Z}/2\mathbf{Z}$ spinors, which have appeared in various…

Differential Geometry · Mathematics 2026-04-15 Gorapada Bera , Thomas Walpuski

We propose the Roe C*-algebra from coarse geometry as a model for topological phases of disordered materials. We explain the robustness of this C*-algebra and formulate the bulk-edge correspondence in this framework. We describe the map…

Mathematical Physics · Physics 2019-04-30 Eske Ellen Ewert , Ralf Meyer

We introduce and systematically develop two classes of discrete integrable operators: those with $2\times 2$ matrix kernels and those possessing general differential kernels, thereby generalizing the discrete analogue previously studied. A…

Exactly Solvable and Integrable Systems · Physics 2025-11-10 Huan Liu

In this work, the notion of a twisted partial Hopf action is introduced as a unified approach for twisted partial group actions, partial Hopf actions and twisted actions of Hopf algebras. The conditions on partial cocycles are established…

Rings and Algebras · Mathematics 2015-11-12 Marcelo Muniz S. Alves , Eliezer Batista , Michael Dokuchaev , Antonio Paques

We introduce and study a $K$-theory of twisted bundles for associative algebras $A(\mathfrak g)$ of formal series with an infinite-Lie algebra coefficients over arbitrary compact topological spaces. Fibers of such bundles are given by…

Functional Analysis · Mathematics 2022-07-08 A. Zuevsky

We compute explicitly the K-groups of some boundary groupoid C*-algebras with exponential isotropy subgroups. Then we derive index formulas that computes the K-theoretic and Fredholm indexes of elliptic (respectively totally elliptic)…

K-Theory and Homology · Mathematics 2018-04-30 Bing Kwan So

When the index bundle of a longitudinal Dirac type operator is transversely smooth, we define its Chern character in Haefliger cohomology and relate it to the Chern character of the $K-$theory index. This result gives a concrete connection…

Geometric Topology · Mathematics 2007-05-23 Moulay Benameur , James Heitsch

We establish a new group-theoretic realization of the basic representations of the twisted affine and twisted toroidal algebras of ADE types in the same spirit of our new approach to the McKay correspondence. Our vertex operator…

Quantum Algebra · Mathematics 2020-09-08 Naihuan Jing , Weiqiang Wang

We use a result of Barron, Dong and Mason to give a natural isomorphism between the category of twisted modules and the category of quasi-modules of a certain type for a general vertex operator algebra.

Quantum Algebra · Mathematics 2007-05-23 Haisheng Li

The real theory of the Dunkl operators has been developed very extensively, while there still lacks the corresponding complex theory. In this paper we introduce the complex Dunkl operators for certain Coxeter groups. These complex Dunkl…

Complex Variables · Mathematics 2009-12-31 Guangbin Ren , Helmuth R. Malonek

Generalized product formulas and index transforms, involving products of Whittaker's functions of different indices are established and investigated. The corresponding inversion formulas are found. Particular cases cover index transforms…

Classical Analysis and ODEs · Mathematics 2025-06-09 Semyon Yakubovich