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Let $V$ be a connected $3$-dimensional handlebody of finite genus at least $3$. We prove that the handlebody group $\mathrm{Mod}(V)$ is superrigid for measure equivalence, i.e. every countable group which is measure equivalent to…

Group Theory · Mathematics 2025-01-31 Sebastian Hensel , Camille Horbez

We describe conditions that characterize amenability for groups in terms of positive definite functions valued in a von Neumann algebra.

Operator Algebras · Mathematics 2022-02-02 Mikaël Pichot , Erik Séguin

We extend the classical van der Corput inequality to the real line. As a consequence, we obtain a simple proof of the Wiener-Wintner theorem for the $\mathbb{R}$-action which assert that for any family of maps $(T_t)_{t \in \mathbb{R}}$…

Dynamical Systems · Mathematics 2021-07-20 el Houcein el Abdalaoui

We undertake a comprehensive study of measure equivalence between general locally compact, second countable groups, providing operator algebraic and ergodic theoretic reformulations, and complete the classification of amenable groups within…

Group Theory · Mathematics 2021-01-13 Juhani Koivisto , David Kyed , Sven Raum

Let $U$ be a compact semisimple Lie group with complexification $G$ and associated Cartan involution $\Theta$. Let $\nu$ be an involutive complex Lie group automorphism of $G$ commuting with $\Theta$, and consider the associated semisimple…

Quantum Algebra · Mathematics 2020-02-03 Kenny De Commer

Let G denote either a special orthogonal group or a symplectic group defined over the complex numbers. We prove the following saturation result for G: given dominant weights \lambda^1, ..., \lambda^r such that the tensor product…

Representation Theory · Mathematics 2011-11-24 Steven V Sam

A manifestly gauge invariant continuous renormalization group flow equation is constructed for pure SU(N) gauge theory. The formulation makes sense without gauge fixing and manifestly gauge invariant calculations may thus be carried out.…

High Energy Physics - Theory · Physics 2009-10-31 Tim R. Morris

In this talk, I will survey recent progress made on the classification of von Neumann algebras arising from countable groups and their actions on probability spaces. In particular, I will present the first results which provide classes of…

Operator Algebras · Mathematics 2012-12-04 Adrian Ioana

It is shown by Houdayer-Isono that a group measure space von Neumann algebra is a full factor if the group is countable discrete and bi-exact, and the action is strongly ergodic, essentially free and non-singular. Recently, bi-exactness for…

Operator Algebras · Mathematics 2022-03-16 Yuta Michimoto

The covariance group for general relativity, the diffeomorphisms, is replaced by a group of coordinate transformations which contains the diffeomorphisms as a proper subgroup. The larger group is defined by the assumption that all observers…

General Relativity and Quantum Cosmology · Physics 2012-08-27 Dave Pandres,

We investigate locally compact topological groups for which a generalized analogue of Heisenberg uncertainty inequality hold. In particular, it is shown that this inequality holds for $\mathbb{R}^n \times K$ (where $K$ is a separable…

Analysis of PDEs · Mathematics 2015-08-12 Ashish Bansal , Ajay Kumar

We present a simple remark that assures that the invariant theory of certain real Lie groups coincides with that of the underlying affine, real algebraic groups. In particular, this result applies to the non-compact orthogonal or symplectic…

Differential Geometry · Mathematics 2019-03-12 A. Gordillo , J. Navarro , P. Sancho

In this paper we complete in several aspects the picture of locally compact quantum groups. First of all we give a definition of a locally compact quantum group in the von Neumann algebraic setting and show how to deduce from it a…

Operator Algebras · Mathematics 2007-05-23 Johan Kustermans , Stefaan Vaes

We give a survey of various recent developments in orbit equivalence and measured group theory. This subject aims at studying infinite countable groups through their measure preserving actions.

Group Theory · Mathematics 2010-09-02 Damien Gaboriau

The issue of implementing the principle of general relativity in Einstein equations has been widely discussed, since Kretschmann's well-known criticism stated that general covariance of the Einstein equations is not suffice to express the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Mauricio Leston , Rafael Ferraro

Given an irreducible lattice $\Gamma$ in the product of higher rank simple Lie groups, we prove a co-finiteness result for the $\Gamma$-invariant von Neumann subalgebras of the group von Neumann algebra $\mathcal{L}(\Gamma)$, and for the…

Operator Algebras · Mathematics 2022-02-10 Mehrdad Kalantar , Nikolaos Panagopoulos

In this paper, we use the tools of nonabelian duality to formulate and prove a far-reaching generalization of the Stone-von Neumann Theorem to modular representations of actions and coactions of locally compact groups on elementary $…

Operator Algebras · Mathematics 2022-06-22 Lucas Hall , Leonard Huang , John Quigg

We get three types of results on measure equivalence rigidity; direct product groups of Ozawa's class $\mathcal{S}$ groups, wreath product groups and amalgamated free products. We prove measure equivalence factorization results on direct…

Group Theory · Mathematics 2014-08-07 Hiroki Sako

We give a characterisation of factoriality of the groupoid von Neumann algebra $L(\mathcal{G})$ associated to a discrete measured groupoid $(\mathcal{G},\mu)$. We introduce the notion of groupoids with `infinite conjugacy classes' and show…

Operator Algebras · Mathematics 2024-12-10 Tey Berendschot , Soham Chakraborty , Milan Donvil , Se-Jin Kim

We prove a generalization of the orthogonality relations of Duflo and Moore for ergodic, trace-preserving group actions on von Neumann algebras that are integrable in a suitable sense. We also obtain convolution inequalities that generalize…

Operator Algebras · Mathematics 2026-05-28 Ulrik Enstad , Hannes Wendt
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