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Related papers: Compact Operators in Regular LCQ Groups

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R. Ellis showed in 1960 that every discrete group acts freely on its Stone-Cech compactification. We extend this result to discrete quantum groups with low duals. The method of proof is different from the earlier proofs in the classical…

Operator Algebras · Mathematics 2026-03-18 Pekka Salmi

Recently, it has been established that the discrete star Laplace and the discrete Dirac operator, i.e. the discrete versions of their continuous counterparts when working on the standard grid, are rotation-invariant. This was done starting…

Mathematical Physics · Physics 2017-01-31 Hilde De Ridder , Franciscus Sommen

In 1972, B. E. Johnson proved that a locally compact group $G$ is amenable if and only if certain Hochschild cohomology groups of its convolution algebra $L^1(G)$ vanish. Similarly, $G$ is compact if and only if $L^1(G)$ is biprojective: In…

Functional Analysis · Mathematics 2007-05-23 Volker Runde

Let $p$ be a prime number, and let $\mathbb{G}$ be a compact $p$-adic Lie group. This work provides multiplier theorems for invariant operators on $\mathbb{G}$ acting on $L^r_\alpha(\mathbb{G})$, $1<r<\infty$, $\alpha>0$, in terms of the…

Representation Theory · Mathematics 2026-03-25 J. P. Velasquez-Rodriguez

Let X be a Hermitian complex space of pure dimension n. We show that the d-bar-Neumann operator on (p,q)-forms is compact at isolated singularities of X if q>0 and p+q is not equal to n-1 or n. The main step is the construction of compact…

Complex Variables · Mathematics 2010-07-27 Jean Ruppenthal

We consider a class of operators defined by taking averages along polynomial sequences in discrete nilpotent groups. In this paper we prove $L^2$ boundedness of discrete singular Radon transforms along general polynomial sequences in…

Classical Analysis and ODEs · Mathematics 2012-05-01 Alexandru D. Ionescu , Akos Magyar , Stephen Wainger

We introduce the Property of Rapid Decay for discrete quantum groups by equivalent characterizations that generalize the classical ones. We then investigate examples, proving in particular the Property of Rapid Decay for unimodular free…

Operator Algebras · Mathematics 2020-06-04 Roland Vergnioux

Let G be a connected, simply connected, simple complex algebraic group and let e be a primitive l-th root of 1, with l odd and 3 does not divide l if G is of type G_{2}. We determine all Hopf algebra quotients of the quantized coordinate…

Quantum Algebra · Mathematics 2014-01-14 Nicolas Andruskiewitsch , Gaston Andres Garcia

We introduce the notion of graphical discreteness to group theory. A finitely generated group is graphically discrete if whenever it acts geometrically on a locally finite graph, the automorphism group of the graph is compact-by-discrete.…

Group Theory · Mathematics 2025-11-20 Alex Margolis , Sam Shepherd , Emily Stark , Daniel Woodhouse

A topological group is locally pseudocompact if it contains a non-empty open set with pseudocompact closure. In this note, we prove that if G is a group with the property that every closed subgroup of G is locally pseudocompact, then G_0 is…

General Topology · Mathematics 2011-09-27 Dikran Dikranjan , Gábor Lukács

Let $\mathbf{G}$ be an algebraic group over a local field $\mathbf k$ of characteristic zero. We show that the locally compact group $\mathbf G(\mathbf k)$ consisting of the $\mathbf k$-rational points of $\mathbf G$ is of type I. Moreover,…

Representation Theory · Mathematics 2020-03-06 Bachir Bekka , Siegfried Echterhoff

We establish the $L^p$-$L^q$-boundedness of subelliptic pseudo-differential operators on a compact Lie group $G$. Effectively, we deal with the $L^p$-$L^q$-bounds for operators in the sub-Riemmanian setting because the subelliptic classes…

Analysis of PDEs · Mathematics 2023-10-26 Duván Cardona , Julio Delgado , Vishvesh Kumar , Michael Ruzhansky

By [6], a minimal group $G$ is called $z$-minimal if $G/Z(G)$ is minimal. In this paper, we present the $z$-Minimality Criterion for dense subgroups with some applications to topological matrix groups. For a locally compact group $G$, let…

General Topology · Mathematics 2024-07-01 Dekui Peng , Menachem Shlossberg

Let G/H be a strongly regular homogeneous space such that H is a Lie group of inner type. We show that G/H admits a proper action of a discrete non-virtually abelian subgroup of G if and only if G/H admits a proper action of a subgroup L of…

Differential Geometry · Mathematics 2015-01-29 Maciej Bochenski

For a locally compact group $G$ we look at the group algebras $C_0(G)$ and $C_r^*(G)$, and we let $f\in C_0(G)$ act on $L^2(G)$ by the multiplication operator $M(f)$. We show among other things that the following properties are equivalent:…

Operator Algebras · Mathematics 2007-10-02 Magnus B. Landstad , A. Van Daele

The purpose of this paper is to study algebras of singular integral operators on $\mathbb{R}^{n}$ and nilpotent Lie groups that arise when one considers the composition of Calder\'on-Zygmund operators with different homogeneities, such as…

Functional Analysis · Mathematics 2015-11-19 Alexander Nagel , Fulvio Ricci , Elias M. Stein , Stephen Wainger

We use the structure lattice, introduced in Part I, to undertake a systematic study of the class $\mathscr S$ consisting of compactly generated, topologically simple, totally disconnected locally compact groups that are non-discrete. Given…

Group Theory · Mathematics 2017-07-07 Pierre-Emmanuel Caprace , Colin D. Reid , George A. Willis

Let $G$ be a group and let $K$ be a commensurated subgroup of $G$. Then there is a totally disconnected, locally compact (t.d.l.c.) group $\hat{G}_K$ that contains the profinite completion of $K$ as an open compact subgroup and also…

Group Theory · Mathematics 2015-09-03 Colin D. Reid

We describe the global structure of totally disconnected locally compact groups having a linear open compact subgroup. Among the applications, we show that if a non-discrete, compactly generated, topologically simple, totally disconnected…

Group Theory · Mathematics 2019-01-17 Pierre-Emmanuel Caprace , Thierry Stulemeijer

Suppose G is a non-free finitely generated Kleinian group without parabolics which is not a lattice and let C(G) denote the commensurator in PSL(2,C). We prove that if the limit set of G is not a round circle, then C(G) is discrete.…

Geometric Topology · Mathematics 2014-10-01 C. J. Leininger , D. D. Long , A. W. Reid