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Related papers: C*-algebraic partial compact quantum groups

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In this article, we generalize to the case of measured quantum groupoids on a finite basis some important results concerning actions of locally compact quantum groups on C*-algebras [S. Baaj, G. Skandalis and S. Vaes, 2003]. Let $\cal G$ be…

Operator Algebras · Mathematics 2019-10-01 Jonathan Crespo

The aim of this paper is to present the construction of a general family of C*-algebras which includes, as a special case, the "quantum spacetime algebra" introduced by Doplicher, Fredenhagen and Roberts. It is based on an extension of the…

Operator Algebras · Mathematics 2015-07-06 Michael Forger , Daniel V. Paulino

We introduce certain $C^*$-algebras and $k$-graphs associated to $k$ finite dimensional unitary representations $\rho_1,...,\rho_k$ of a compact group $G$. We define a higher rank Doplicher-Roberts algebra $\mathcal{O}_{\rho_1,...,\rho_k}$,…

Operator Algebras · Mathematics 2020-06-26 Valentin Deaconu

The method of geometrical quantization of symplectic manifolds is applied to constructing infinite dimensional irreducible unitary representations of the algebra of functions on the compact quantum group $SU_q(2)$. A formulation of the…

High Energy Physics - Theory · Physics 2009-10-22 G. E. Arutyunov

Consider a C*-algebra $A$ with a comultiplication $\Delta$. This pair is usually thought of as locally compact quantum semi-group. When these notes were written, in 1993, it was not at all clear what the extra assumptions on the…

Operator Algebras · Mathematics 2007-05-23 Alfons Van Daele

We introduce a quantum automorphism group for hypergraphs, which turns out to generalize the quantum automorphism group of Bichon for classical graphs. Further, we show that our quantum automorphism group acts on hypergraph C*-algebras as…

Operator Algebras · Mathematics 2024-05-21 Nicolas Faroß

We address the classification problem for graph $C^*$-algebras of finite graphs (finitely many edges and vertices), containing the class of Cuntz-Krieger algebras as a prominent special case. Contrasting earlier work, we do not assume that…

Operator Algebras · Mathematics 2018-03-05 Søren Eilers , Gunnar Restorff , Efren Ruiz , Adam P. W. Sørensen

We construct C*-dynamical systems for the dynamics of classical infinite particle systems describing harmonic oscillators interacting with arbitrarily many neighbors on lattices, as well on more general structures. Our approach allows…

Operator Algebras · Mathematics 2025-12-19 T. D. H. van Nuland , C. J. F. van de Ven

In this paper, we investigate *-homomorphisms between C*-algebras associated to \'etale groupoids. First, we prove that such a *-homomorphism can be described by closed invariant subsets, groupoid homomorphisms and cocycles under some…

Operator Algebras · Mathematics 2023-08-24 Fuyuta Komura

We study the natural representation of the topological full group of an ample Hausdorff groupoid in the groupoid's complex Steinberg algebra and in its full and reduced C*-algebras. We characterise precisely when this representation is…

Operator Algebras · Mathematics 2024-01-05 Becky Armstrong , Lisa Orloff Clark , Mahya Ghandehari , Eun Ji Kang , Dilian Yang

A C*-algebra is determined to a great extent by the partial order of its commutative C*-algebras. We study order-theoretic properties of this dcpo. Many properties coincide: the dcpo is, equivalently, algebraic, continuous, meet-continuous,…

Operator Algebras · Mathematics 2020-12-03 Chris Heunen , Bert Lindenhovius

This paper argues that the unitary Cuntz semigroup, introduced in [10] and termed Cu$_1$, contains crucial information regarding the classification of non-simple C$^*$-algebras. We exhibit two (non-simple) C$^*$-algebras that agree on their…

Operator Algebras · Mathematics 2022-10-25 Laurent Cantier

We give a concise introduction to (discrete) algebras arising from \'etale groupoids, (aka Steinberg algebras) and describe their close relationship with groupoid C*-algebras. Their connection to partial group rings via inverse semigroups…

Rings and Algebras · Mathematics 2019-01-08 Lisa Orloff Clark , Roozbeh Hazrat

We study the C*-algebras and von Neumann algebras associated with the universal discrete quantum groups. They give rise to full prime factors and simple exact C*-algebras. The main tool in our work is the study of an amenable boundary…

Operator Algebras · Mathematics 2007-09-25 Stefaan Vaes , Roland Vergnioux

We introduce the Rohlin property and the approximate representability for finite group actions on stably projectionless C*-algebras and study their basic properties. We give some examples of finite group actions on the Razak-Jacelon algebra…

Operator Algebras · Mathematics 2013-08-05 Norio Nawata

A group may be considered $C^*$-stable if almost representations of the group in a $C^*$-algebra are always close to actual representations. We initiate a systematic study of which discrete groups are $C^*$-stable or only stable with…

Operator Algebras · Mathematics 2021-04-21 Søren Eilers , Tatiana Shulman , Adam P. W. Sørensen

We show that group C*-algebras of finitely generated, nilpotent groups have finite nuclear dimension. It then follows, from a string of deep results, that the C*-algebra $A$ generated by an irreducible representation of such a group has…

Operator Algebras · Mathematics 2015-05-15 Caleb Eckhardt , Paul McKenney

Motivated by the idea that our access to the spacetime is limited by the resolution of our measuring device, we give a new description of $K$-homology with a finite resolution. G. Yu introduced a $C^*$-algebra called the localization…

K-Theory and Homology · Mathematics 2024-01-17 Ryo Toyota

In this note we analyze the C*-algebra associated with a branched covering both as a groupoid C*-algebra and as a Cuntz-Pimsner algebra. We determine conditions when the algebra is simple and purely infinite. We indicate how to compute the…

Operator Algebras · Mathematics 2007-05-23 Valentin Deaconu , Paul S. Muhly

We show that there is a one-to-one correspondence between compact quantum subgroups of a co-amenable locally compact quantum group $\mathbb{G}$ and certain left invariant C*-subalgebras of $C_0(\mathbb{G})$. We also prove that every compact…

Operator Algebras · Mathematics 2012-01-25 Pekka Salmi