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Related papers: Locally compact quantum groupoid

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We construct the first examples of genuine ergodic discrete measured groupoids that are not isomorphic to any equivalence relation or transformation groupoid. We use a construction due to B.H. Neumann of an uncountable family of pairwise…

Group Theory · Mathematics 2025-10-15 Soham Chakraborty

The Haagerup property for locally compact groups is generalised to the context of locally compact quantum groups, with several equivalent characterisations in terms of the unitary representations and positive-definite functions established.…

Operator Algebras · Mathematics 2016-02-16 Matthew Daws , Pierre Fima , Adam Skalski , Stuart White

We give an example of a locally compact effective Hausdorff, minimal ample groupoid such that its rational homology differs from the $K$-theory of its reduced groupoid $C^*$-algebra. Moreover, we prove that such example satisfies Matui's…

Operator Algebras · Mathematics 2021-04-06 Eduard Ortega , Alvaro Sanchez

For a matched pair of locally compact quantum groups, we construct the double crossed product as a locally compact quantum group. This construction generalizes Drinfeld's quantum double construction. We study C*-algebraic properties of…

Operator Algebras · Mathematics 2007-05-23 Saad Baaj , Stefaan Vaes

This is the last part of a series of three papers on the subject. In the first part we have considered the duality of algebraic quantum groups. In that paper, we use the term algebraic quantum group for a regular multiplier Hopf algebra…

Quantum Algebra · Mathematics 2023-04-27 Alfons Van Daele

The purpose of the current paper is twofold: to provide a conceptual link between the quantization framework based on Lie integration of algebroids proposed by N.P. Landsman in the book "Mathematical Topics between Classical and Quantum…

Mathematical Physics · Physics 2020-12-15 Jan Marcin Głowacki

Locally conformal symplectic (l.c.s.) groupoids are introduced as a generalization of symplectic groupoids. We obtain some examples and we prove that l.c.s. groupoids are examples of Jacobi groupoids in the sense of \cite{IM}. Finally, we…

Differential Geometry · Mathematics 2007-05-23 D. Iglesias-Ponte , J. C. Marrero

Given a semigroup of local homeomorphisms on a compact space X we consider the corresponding semigroup of *-endomorphisms on C(X) and discuss the possibility of extending it to an interaction group, a concept recently introduced by the…

Operator Algebras · Mathematics 2010-03-16 Ruy Exel , Jean Renault

We present versions of several classical results on harmonic functions and Poisson boundaries in the setting of locally compact quantum groups. In particular, the Choquet--Deny theorem holds for compact quantum groups; also, the result of…

Operator Algebras · Mathematics 2014-04-08 Mehrdad Kalantar , Matthias Neufang , Zhong-Jin Ruan

We prove a Freiman-type theorem for locally compact abelian groups. If A is a subset of a locally compact abelian group with Haar measure m and m(nA) < n^dm(A) for all n>d log d then we describe A in a way which is tight up to logarithmic…

Classical Analysis and ODEs · Mathematics 2010-04-02 Tom Sanders

We define the Furstenberg boundary of a locally compact Hausdorff \'etale groupoid, generalising the Furstenberg boundary for discrete groups, by providing a construction of a groupoid-equivariant injective envelope. Using this injective…

Operator Algebras · Mathematics 2020-01-31 Clemens Borys

This paper compares two generalizations of Heisenberg groups and studies their connection to one of the major open problems in the field of locally compact abelian groups, namely the description of the self-dual locally compact abelian…

Group Theory · Mathematics 2017-09-11 Marco Bonatto , Dikran Dikranjan

Metric noncommutative geometry, initiated by Alain Connes, has known some great recent developments under the impulsion of Rieffel and the introduction of the category of compact quantum metric spaces topologized thanks to the quantum…

Operator Algebras · Mathematics 2011-10-10 Frederic Latremoliere

The following paper is devoted to the study of type I locally compact quantum groups. We show how various operators related to the modular theory of the Haar integrals on $\mathbb{G}$ and $\widehat{\mathbb{G}}$ act on the level of direct…

Quantum Algebra · Mathematics 2020-08-06 Jacek Krajczok

Given an action of a discrete quantum group (in the sense of Van Daele, Kustermans and Effros-Ruan) ${\cal A}$ on a $C^*$-algebra ${\cal C}$, satisfying some regularity assumptions resembling the proper $\Gamma$-compact action for a…

K-Theory and Homology · Mathematics 2007-05-23 Debashish Goswami , A. O. Kuku

If a compact quantum group acts faithfully and smoothly (in the sense of Goswami 2009) on a smooth, compact, oriented, connected Riemannian manifold such that the action induces a natural bimodule morphism on the module of sections of the…

Operator Algebras · Mathematics 2014-11-17 Debashish Goswami

We introduce a relative tensor product of $C^{*}$-modules and a spatial fiber product of $C^{*}$-algebras that are analogues of Connes' fusion of correspondences and the fiber product of von Neumann algebras introduced by Sauvageot,…

Operator Algebras · Mathematics 2013-07-02 Thomas Timmermann

Let $\mathbb{G}$ be a locally compact quantum group. We give a 1-1 correspondence between group-like projections in $L^\infty(\mathbb{G})$ preserved by the scaling group and idempotent states on the dual quantum group…

Operator Algebras · Mathematics 2018-01-10 Ramin Faal , Paweł Kasprzak

We discuss various notions generalizing the concept of a homogeneous space to the setting of locally compact quantum groups. On the von Neumann algebra level we find an interesting duality for such objects. A definition of a quantum…

Operator Algebras · Mathematics 2014-11-10 Paweł Kasprzak , Piotr M. Sołtan

Convolution semigroups of states on a quantum group form the natural noncommutative analogue of convolution semigroups of probability measures on a locally compact group. Here we initiate a theory of weakly continuous convolution semigroups…

Operator Algebras · Mathematics 2009-10-28 J. Martin Lindsay , Adam Skalski