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We compute K-theory for the reduced group C*-algebras of generalized Lamplighter groups.

K-Theory and Homology · Mathematics 2020-07-07 Xin Li

We compute K-theory for ring C*-algebras in the case of higher roots of unity and thereby completely determine the K-theory for ring C*-algebras attached to rings of integers in arbitrary number fields.

Operator Algebras · Mathematics 2025-04-08 Xin Li , Wolfgang Lück

A theory of reduction of Lie-Jordan Banach algebras with respect to either a Jordan ideal or a Lie-Jordan subalgebra is presented. This theory is compared with the standard reduction of C*-algebras of observables of a quantum system in the…

Mathematical Physics · Physics 2015-06-04 F. Falceto , L. Ferro , A. Ibort , G. Marmo

We quantize abelian Yang-Mills theory on Riemannian manifolds with boundaries in any dimension. The quantization proceeds in two steps. First, the classical theory is encoded into an axiomatic form describing solution spaces associated to…

High Energy Physics - Theory · Physics 2018-09-28 Homero G. Díaz-Marín , Robert Oeckl

We compute the K-theory of ring C*-algebras for polynomial rings over finite fields. The key ingredient is a duality theorem which we had obtained in a previous paper. It allows us to show that the K-theory of these algebras has a ring…

Operator Algebras · Mathematics 2009-11-30 Joachim Cuntz , Xin Li

A new notion of controllability for quantum systems that takes advantage of the linear superposition of quantum states is introduced. We call such notion von Neumann controllabilty and it is shown that it is strictly weaker than the usual…

Quantum Physics · Physics 2015-06-04 A. Ibort , J. M. Pérez-Pardo

It is proved that, for each pair (m,n) of non-negative integers, there is a Banach space X for which the group K_0(B(X)) is isomorphic to m copies of the integers and the group K_1(B(X)) is isomorphic to n copies of the integers. Along the…

Functional Analysis · Mathematics 2008-02-03 Niels Jakob Laustsen

In this project, we will develop the theory of Banach algebras and prove two celebrated theorems, the Gelfand representation theorem and the GKZ theorem. We will then proceed to develop the theory of $C^*$-algebras and prove the…

Operator Algebras · Mathematics 2021-04-06 Senan Sekhon

The principles of the theory of quantum groups are reviewed from the point of view of the possibility of their use for deformations of symmetries in physical models. The R-matrix approach to the theory of quantum groups is discussed in…

Quantum Algebra · Mathematics 2023-08-02 A. P. Isaev

R-matrices are the solutions of the Yang-Baxter equation. At the origin of the quantum group theory, they may be interpreted as intertwining operators. Recent advances have been made independently in different directions. Maulik-Okounkov…

Quantum Algebra · Mathematics 2020-05-18 David Hernandez

We study the C*-algebra crossed product $C_0(X)\rtimes G$ of a locally compact group $G$ acting properly on a locally compact Hausdorff space $X$. Under some mild extra conditions, which are automatic if $G$ is discrete or a Lie group, we…

K-Theory and Homology · Mathematics 2010-12-24 Heath Emerson , Siegfried Echterhoff

These notes cover the contents of three survey lectures held at the ICTP Trieste Summer school on High dimensional manifold theory 2001. They introduce techniques coming from the theory of operator algebras. We will focus on the basic…

Geometric Topology · Mathematics 2007-05-23 Thomas Schick

Recent work of Jonathan Campbell and Inna Zakharevich has focused on building machinery for studying scissors congruence problems via algebraic $K$-theory, and applying these tools to studying the Grothendieck ring of varieties. In this…

Algebraic Topology · Mathematics 2021-12-07 Renee S. Hoekzema , Mona Merling , Laura Murray , Carmen Rovi , Julia Semikina

We classify graph C*-algebras, namely, Cuntz-Krieger algebras associated to the Bass-Hashimoto edge incidence operator of a finite graph. This is done by a purely graph theoretical calculation of the K-theory and the position of the unit…

Operator Algebras · Mathematics 2007-05-23 Gunther Cornelissen , Oliver Lorscheid , Matilde Marcolli

For special universal $C^*$-algebras associated to $k$-semigraphs we present the universal representations of these algebras, prove a Cuntz--Krieger uniqueness theorem, and compute the $K$-theory. These $C^*$-algebras seem to be the most…

Operator Algebras · Mathematics 2013-06-24 Bernhard Burgstaller

We give an operator algebraic model for the first group of the unit spectrum $gl_1(KU)$ of complex topological K-theory, i.e. $[X, BGL_1(KU)]$, by bundles of stabilized infinite Cuntz C*-algebras $O_{\infty} \otimes \K$. We develop similar…

Algebraic Topology · Mathematics 2015-09-03 Marius Dadarlat , Ulrich Pennig

We present an operator-algebraic approach to the quantization and reduction of lattice field theories. Our approach uses groupoid C*-algebras to describe the observables and exploits Rieffel induction to implement the quantum gauge…

Mathematical Physics · Physics 2018-10-19 Francesca Arici , Ruben Stienstra , Walter D. van Suijlekom

A major direction in the theory of cluster algebras is to construct (quantum) cluster algebra structures on the (quantized) coordinate rings of various families of varieties arising in Lie theory. We prove that all algebras in a very large…

Quantum Algebra · Mathematics 2015-08-14 K. R. Goodearl , M. T. Yakimov

Decomposition complexity for metric spaces was recently introduced by Guentner, Tessera, and Yu as a natural generalization of asymptotic dimension. We prove a vanishing result for the continuously controlled algebraic K-theory of bounded…

K-Theory and Homology · Mathematics 2018-05-09 Daniel A. Ramras , Romain Tessera , Guoliang Yu

We study (von Neumann) regular $^*$-subalgebras of $B(H)$, which we call R$^*$-algebras. The class of R$^*$-algebras coincides with that of "E$^*$-algebras that are pre-C$^*$-algebras" in the sense of Z. Sz\H{u}cs and B. Tak\'acs. We give…

Operator Algebras · Mathematics 2022-03-23 Michiya Mori