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Given a finite, directed, connected graph $\Gamma$ equipped with a weighting $\mu$ on its edges, we provide a construction of a von Neumann algebra equipped with a faithful, normal, positive linear functional…

Operator Algebras · Mathematics 2018-11-19 Michael Hartglass , Brent Nelson

We say that a finitely generated group $\Gamma$ is self-simulable if every effectively closed action of $\Gamma$ on a closed subset of $\{\texttt{0},\texttt{1}\}^{\mathbb{N}}$ is the topological factor of a $\Gamma$-subshift of finite type.…

Group Theory · Mathematics 2025-02-25 Sebastián Barbieri , Mathieu Sablik , Ville Salo

In this paper, we consider random walks on the isometry groups of general metric spaces. Under some mild conditions, we show that if two non-elementary random walks on a discrete subgroup of the isometry group have non-singular stationary…

Geometric Topology · Mathematics 2026-01-08 Dongryul M. Kim , Andrew Zimmer

We give a simple proof of the finite presentation of Sela's limit groups by using free actions on R^n-trees. We first prove that Sela's limit groups do have a free action on an R^n-tree. We then prove that a finitely generated group having…

Group Theory · Mathematics 2014-11-11 Vincent Guirardel

We consider a variant of random walks on finite groups. At each step, we choose an element from a set of generators ("directions") uniformly, and an integer from a power law ("speed") distribution associated with the chosen direction. We…

Probability · Mathematics 2022-03-14 Laurent Saloff-Coste , Yuwen Wang

We study probability measure on $\mathrm{Hom}(H,G)$, where $G$ is a finite group and $H$ a finitely generated subgroup of a finitely generated free group $F$, obtained by pushing forward the uniform random homomorphisms $\mathrm{Hom}(F,G)$…

Group Theory · Mathematics 2026-02-16 Shrinit Singh

The classical Gaussian functor associates to every orthogonal representation of a locally compact group $G$ a probability measure preserving action of $G$ called a Gaussian action. In this paper, we generalize this construction by…

Dynamical Systems · Mathematics 2020-10-23 Yuki Arano , Yusuke Isono , Amine Marrakchi

For finitely supported random walks on finitely generated groups $G$ we prove that the identity map on $G$ extends to a continuous equivariant surjection from the Martin boundary to the Floyd boundary, with preimages of conical points being…

Group Theory · Mathematics 2017-12-07 Ilya Gekhtman , Victor Gerasimov , Leonid Potyagailo , Wenyuan Yang

Using an analogy with the rank theorem in differential geometry, it is shown that for a finite $n$-tuple $X$ in a tracial von Neumann algebra and any finite $m$-tuple $F$ of $*$-polynomials in $n$ noncommuting indeterminates,…

Operator Algebras · Mathematics 2016-02-16 Kenley Jung

For a metric space $X$ with a compatible measure $\mu$, Genevois and Tessera defined the Scaling Group of $(X,\mu)$ as the subgroup $\Gamma$ of $\mathbb{R}_{>0}$ of positive real numbers $\gamma$ for which there are quasi-isometries of $X$…

Metric Geometry · Mathematics 2024-12-17 Daniel N. Levitin

We study the isoperimetric and spectral profiles of certain families of finitely generated groups defined via actions on labelled Schreier graphs and simple {\em gluing} of such. In one of our simplest constructions---the {\em…

Probability · Mathematics 2020-09-01 Laurent Saloff-Coste-Costeb , Tianyi Zheng

We develop a relative boundary theory for actions of discrete groups on compact spaces and use it to derive rigidity results for reduced crossed products. For a discrete group $\Gamma$ acting on a compact space $X$ and a subgroup $H$, we…

Operator Algebras · Mathematics 2026-01-08 Tattwamasi Amrutam , Chunlin Liu

We show that, whenever Gamma is a countable abelian group and Delta is a finitely-generated subgroup of Gamma, a generic measure-preserving action of Delta on a standard atomless probability space (X,mu) extends to a free measure-preserving…

Logic · Mathematics 2013-02-18 Julien Melleray

We introduce a quantitative notion of lawlessness for finitely generated groups, encoded by the "lawlessness growth function" $\mathcal{A}_{\Gamma} : \mathbb{N} \rightarrow \mathbb{N}$. We show that $\mathcal{A}_{\Gamma}$ is bounded iff…

Group Theory · Mathematics 2022-01-11 Henry Bradford

Let $\Gamma$ be a discrete countable group acting isometrically on a measurable field $\mathbf{X}$ of CAT(0)-spaces of finite telescopic dimension over some ergodic standard Borel probability $\Gamma$-space $(\Omega,\mu)$. If $\mathbf{X}$…

Geometric Topology · Mathematics 2025-06-05 Filippo Sarti , Alessio Savini

Let $G$ be a finite group of order $n$, and $Z_G=\mathbb{Z}\langle\zeta_{i,g}\mid g\in G,\ i=1,2,\dots,n\rangle$ be the free generic algebra, with canonical action of $G$ according to $(\zeta_{i,g})^x=\zeta_{i,x^{-1}g}$. It is proved that…

Rings and Algebras · Mathematics 2019-05-22 Piotr Grzeszczuk

Let $\Gamma$ be an amenable countable discrete group. Fix an ergodic free nonsingular action of $\Gamma$ on a nonatomic standard probability space. Let $G$ be a compactly generated locally compact second countable group such that the…

Dynamical Systems · Mathematics 2019-09-04 Alexandre I. Danilenko

Let $\Gamma$ be a finitely generated group, and let $\mu$ be a nondegenerate, finitely supported probability measure on $\Gamma$. We show that every co-compact $\Gamma$ action on a locally compact Hausdorff space admits a nonzero…

Group Theory · Mathematics 2025-09-16 Mohammedsaid Alhalimi , Tom Hutchcroft , Minghao Pan , Omer Tamuz , Tianyi Zheng

We study random torsion-free nilpotent groups generated by a pair of random words of length $\ell$ in the standard generating set of $U_n(\mathbb{Z})$. Specifically, we give asymptotic results about the step properties of the group when the…

Group Theory · Mathematics 2016-02-04 Kelly Delp , Tullia Dymarz , Anschel Schaffer-Cohen

Random walks in a finite Abelian group $G$ are studied. They use Markov chains with doubly stochastic transition matrices, in a Birkhoff subpolytope ${\cal B}(G)$ associated with the group $G$. It is shown that all future probability…

Mathematical Physics · Physics 2026-03-10 A. Vourdas