English
Related papers

Related papers: On Lesieur's Measured Quantum Groupoids

200 papers

We introduce an axiomatization of the notion of a semidirect product of locally compact quantum groups and study properties. Our approach is slightly different from the one introduced in the thesis of S.~Roy and, unlike the investigations…

Operator Algebras · Mathematics 2014-10-17 Paweł Kasprzak , Piotr M. Sołtan

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

In this article, when G is a locally compact quantum group, we associate to a braided-commutative G-Yetter-Drinfel'd algebra $(N,a,\hat{a})$ equipped with a normal faithful semi-finite weight verifying some appropriate condition, a…

Operator Algebras · Mathematics 2017-03-21 Michel Enock , Thomas Timmermann

The purpose of this Note is to unify quantum groups and star-products under a general umbrella: quantum groupoids. It is shown that a quantum groupoid naturally gives rise to a Lie bialgebroid as a classical limit. The converse question,…

q-alg · Mathematics 2009-10-30 Ping Xu

Alain Connes introduced the use of Lie groupoids in noncommutative geometry in his pioneering work on the index theory of foliations. In the present paper, we recall the basic notion involved: groupoids, their C*-algebras, their…

Operator Algebras · Mathematics 2019-07-12 Claire Debord , Georges Skandalis

Using the theory of measurable categories developped by Yetter in work in preparation, we provide a notion of representations of 2-groups more well-suited to physically and geometrically interesting examples than that proposed in…

Quantum Algebra · Mathematics 2007-05-23 L. Crane , D. N. Yetter

A rigorous mathematical theory of dimensional analysis, systematically accounting for the use of physical quantities in science and engineering, perhaps surprisingly, was not developed until relatively recently. We claim that this has…

Mathematical Physics · Physics 2021-08-20 Carlos Zapata-Carratala

In this paper, we streamline the technique of groupoids coarse decomposition for purpose of K-theory computations of groupoids crossed products. This technique was first introduced by Guoliang Yu in his proof of Novikov conjecture for…

Operator Algebras · Mathematics 2020-10-06 Hervé Oyono-Oyono

The postulates of von Neumann and L\"uders concerning measurements in quantum mechanics are discussed and criticized in the context of a simple model proposed by Gisin. The main purpose of our paper is to analyze some mathematical aspects…

Quantum Physics · Physics 2022-12-07 Jürg Fröhlich , Zhou Gang

We generalize in two steps the quantized action of the modular group on $q$-deformed real numbers introduced by Morier-Genoud and Ovsienko. First, we let the projective general linear group $PGL_2(\mathbb{Z})$ act on $q$-real numbers via a…

Combinatorics · Mathematics 2025-03-05 Perrine Jouteur

A fundamental feature of quantum groups is that many come in pairs of mutually dual objects, like finite-dimensional Hopf algebras and their duals, or quantisations of function algebras and of universal enveloping algebras of Poisson-Lie…

Quantum Algebra · Mathematics 2014-03-24 Thomas Timmermann

We introduce C*-pseudo-multiplicative unitaries and concrete Hopf C*-bimodules for the study of quantum groupoids in the setting of C*-algebras. These unitaries and Hopf C*-bimodules generalize multiplicative unitaries and Hopf C*-algebras…

Operator Algebras · Mathematics 2013-07-02 Thomas Timmermann

These are notes of a seminar given at the 30th International Symposium on the Theory of Elementary Particles, Berlin-Buckow, August 1996. The material is derived from collaborations with E. Cremmer and J.-L. Gervais, and C. Klimcik, and is…

High Energy Physics - Theory · Physics 2009-10-30 Jens Schnittger

In a recent article of Kenny De Commer, was investigated a Morita equivalence between locally compact quantum groups, in which a measured quantum groupoid, of basis $\mathbb{C}^2$, was constructed as a linking object. Here, we generalize…

Operator Algebras · Mathematics 2012-09-19 Michel Enock

Finite quantum groupoids can be described in many equivalent ways: In terms of the weak Hopf C*-algebras of B\"ohm, Nill, and Szlach\'anyi or the finite-dimensional Hopf-von Neumann bimodules of Vallin, and in terms of finite-dimensional…

Operator Algebras · Mathematics 2007-11-12 Thomas Timmermann

The unitary dynamics of quantum systems can be modeled as a trajectory on a Riemannian manifold. This theoretical framework naturally yields a purely geometric interpretation of computational complexity for quantum algorithms, a notion…

Quantum Physics · Physics 2025-07-25 Alberto Acevedo , Antonio Falco

We formalize Feynman's construction of the quantum mechanical path integral. To do this, we shift the emphasis in differential geometry from the tangent bundle onto the pair groupoid. This allows us to use the van Est map and the piecewise…

Differential Geometry · Mathematics 2024-02-27 Joshua Lackman

We show how to construct a compact quantum metric space from a proper continuous length function on an \'etale groupoid with compact unit space, where the unit space additionally has the structure of a compact metric space. Using compactly…

Operator Algebras · Mathematics 2026-04-10 Are Austad

We survey the concept of multiplicativity from its initial appearance in the theory of Poisson-Lie groups to the far-reaching generalizations, for multivectors and differential forms in the geometry and the generalized geometry of Lie…

Symplectic Geometry · Mathematics 2016-08-05 Yvette Kosmann-Schwarzbach

We introduce a notion of metric on a Lie groupoid, compatible with multiplication, and we study its properties. We show that many families of Lie groupoids admit such metrics, including the important class of proper Lie groupoids. The…

Differential Geometry · Mathematics 2018-04-03 Matias L. del Hoyo , Rui Loja Fernandes