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We extend the notion of Rokhlin dimension from topological dynamical systems to $C^*$-correspondences. We show that in the presence of finite Rokhlin dimension and a mild quasidiagonal-like condition (which, for example, is automatic for…

Operator Algebras · Mathematics 2016-08-12 N. P. Brown , A. Tikuisis , A. M. Zelenberg

Let $G$ be a compact Lie group. We study a class of Hamiltonian $(G \times S^{1})$-manifolds decorated with a function $s$ with certain equivariance properties, under conditions on the $G$-action which we call of (semi-)linear type. In this…

Symplectic Geometry · Mathematics 2024-06-04 Jonathan Fisher , Lisa Jeffrey , Alessandro Malusà , Steven Rayan

The equivariant coarse index is well-understood and widely used for actions by discrete groups. We extend the definition of this index to general locally compact groups. We use a suitable notion of admissible modules over $C^*$-algebras of…

K-Theory and Homology · Mathematics 2022-07-05 Hao Guo , Peter Hochs , Varghese Mathai

In this note we prove the following theorem: Let $G$ be a compact Lie group acting on a compact symplectic manifold $M$ in a Hamiltonian fashion. If $L$ is an $l$-dimensional closed invariant submanifold of $M$, on which the $G$-action is…

Symplectic Geometry · Mathematics 2007-05-23 Yildiray Ozan

In this paper we compute the K-theory (algebraic and topological) and entire periodic cyclic homology for compact quantum groups, define Chern characters between them and show that the Chern characters in both topological and algebraic…

Quantum Algebra · Mathematics 2014-06-09 Do Ngoc Diep , Aderemi O. Kuku , Nguyen Quoc Tho

We present an explicit formula for the $K$-theory of the $C^*$-algebra associated with a relative generalized Boolean dynamical system $(\CB, \CL, \theta, \CI_\af; \CJ)$. In particular, we find concrete generators for the $K_1$-group of…

Operator Algebras · Mathematics 2025-09-17 Toke Meier Carlsen , Eun Ji Kang

Let A and B be $C^*$-algebras, A separable, and B $\sigma$-unital and stable. It is shown that there are natural isomorphisms $E(A,B)=KK(SA,Q(B))=[SA,Q(B)\otimes K]$, where $SA=C_0(0,1)\otimes A$, $[\cdot,\cdot]$ denotes the set of homotopy…

Operator Algebras · Mathematics 2007-05-23 Vladimir Manuilov , Klaus Thomsen

We study the classifying space of a twisted loop group $L_{\sigma}G$ where $G$ is a compact Lie group and $\sigma$ is an automorphism of $G$ of finite order modulo inner automorphisms. Equivalently, we study the $\sigma$-twisted adjoint…

Algebraic Topology · Mathematics 2016-03-09 Thomas Baird

We develop equivariant KK-theory for locally compact groupoid actions by Morita equivalences on real and complex graded C*-algebras. Functoriality with respect to generalised morphisms and Bott periodicity are discussed. We introduce…

K-Theory and Homology · Mathematics 2013-10-16 El-kaïoum M. Moutuou

For any countable discrete group $G$ with a reduced abelian subgroup of finite index, we construct an action $\alpha$ of $G$ on the universal UHF algebra $\Qq$ using an infinite tensor product of permutation representations of $G$ and show…

Operator Algebras · Mathematics 2014-09-26 Michael Sun

We compute the equivariant $K$-theory $K_G^*(G)$ for a simply connected Lie group $G$ (acting on itself by conjugation). We prove that $K_G^*(G)$ is isomorphic to the algebra of Grothendieck differentials on the representation ring. We also…

dg-ga · Mathematics 2007-05-23 Jean-Luc Brylinski , Bin Zhang

Motivated by classical facts concerning closed manifolds, we introduce a strong finiteness property in K-homology. We say that a C*-algebra has uniformly summable K-homology if all its K-homology classes can be represented by Fredholm…

Operator Algebras · Mathematics 2015-12-16 Heath Emerson , Bogdan Nica

Regular algebraic $K$-theory for groups is a homology theory for discrete groups closely connected (but different from) group homology. It also gives a version of algebraic $K$-theory for rings by the simple functorial mapping assigning to…

K-Theory and Homology · Mathematics 2024-10-02 Ulrich Haag

For a (unital) $C^*$-algebra $\cla$, we construct a $C^*$-algebraic discrete quantum group (DQG) $\clq_{\rm aut}(\cla)$, coacting on $\cla$, which is a quantum generalization of ${\text Aut}(\cla)$ in the framework of discrete quantum…

Quantum Algebra · Mathematics 2026-02-17 Debashish Goswami , Suchetana Samadder

We show an equivariant Kirchberg-Phillips-type absorption theorem for pointwise outer actions of discrete amenable groups on Kirchberg algebras with respect to natural model actions on the Cuntz algebras $\mathcal{O}_\infty$ and…

Operator Algebras · Mathematics 2018-10-04 Gabor Szabo

Let G denote a compact connected Lie group with torsion-free fundamental group acting on a compact space X such that all the isotropy subgroups are connected subgroups of maximal rank. Let $T\subset G$ be a maximal torus with Weyl group W.…

Algebraic Topology · Mathematics 2014-02-26 Alejandro Adem , José Manuel Gómez

We define the notion of invariant derivation of a C*-algebra under a compact quantum group action and prove that in certain conditions, such derivations are generators of one parameter automorphism groups.

Operator Algebras · Mathematics 2007-05-23 R. Dumitru , C. Peligrad

We introduce the analog of Bohr compactification for discrete quantum groups on C*-algebra level. The cases of unimodular and general C*-algebraic discrete quantum groups are treated separately. The passage from the former case to the…

Operator Algebras · Mathematics 2016-08-15 P. M. Sołtan

Schuermann's theory of quantum Levy processes, and more generally the theory of quantum stochastic convolution cocycles, is extended to the topological context of compact quantum groups and operator space coalgebras. Quantum stochastic…

Operator Algebras · Mathematics 2008-02-01 J. Martin Lindsay , Adam Skalski

We introduce the Cuntz-Thomsen picture of $\mathcal{C}$-equivariant Kasparov theory, denoted $\mathrm{KK}^\mathcal{C}$, for a unitary tensor category $\mathcal{C}$ with countably many isomorphism classes of simple objects. We use this…

Operator Algebras · Mathematics 2026-03-16 Sergio Girón Pacheco , Kan Kitamura , Robert Neagu