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We classify finite groups in which the centralisers of certain non-central elements are soluble. This includes a full structural description of groups whose non-central element centralisers are all soluble, and a reduction theorem for the…

Group Theory · Mathematics 2025-11-19 Valentina Grazian , Carmine Monetta , Gareth Tracey

We study properties of the Weyl pseudometric associated with an action of a countable amenable group on a compact metric space. We prove that the topological entropy and the number of minimal subsets of the closure of an orbit are both…

Dynamical Systems · Mathematics 2018-08-01 Martha Łącka , Marta Straszak

It is well-known that a Kleinian group is amenable if and only if it is elementary. We establish an analogous property for equivalence relations and foliations with Gromov hyperbolic leaves: they are amenable if and only if they are…

Functional Analysis · Mathematics 2007-05-23 Vadim A. Kaimanovich

We consider expansive group actions on a compact metric space containing a special fixed point denoted by $0$, and endomorphisms of such systems whose forward trajectories are attracted toward $0$. Such endomorphisms are called…

Dynamical Systems · Mathematics 2019-02-18 Ville Salo , Ilkka Törmä

The evidence lower bound (ELBO) is one of the most central objectives for probabilistic unsupervised learning. For the ELBOs of several generative models and model classes, we here prove convergence to entropy sums. As one result, we…

Machine Learning · Statistics 2025-01-17 Jan Warnken , Dmytro Velychko , Simon Damm , Asja Fischer , Jörg Lücke

Let $G$ be a locally compact group. We show that its Fourier algebra $A(G)$ is amenable if and only if $G$ has an abelian subgroup of finite index, and that its Fourier-Stieltjes algebra $B(G)$ is amenable if and only if $G$ has a compact,…

Functional Analysis · Mathematics 2007-05-23 Brian E. Forrest , Volker Runde

Let $G$ be a countable infinite discrete amenable group.It should be noted that a $G$-system $(X,G)$ naturally induces a $G$-system $(\mathcal{M}(X),G)$, where $\mathcal{M}(X)$ denotes the space of Borel probability measures on the compact…

Dynamical Systems · Mathematics 2023-03-06 Kairan Liu , Runju Wei

A direct consequence of Gromov's theorem is that if a group has polynomial geodesic growth with respect to some finite generating set then it is virtually nilpotent. However, until now the only examples known were virtually abelian. In this…

Group Theory · Mathematics 2023-01-27 Alex Bishop , Murray Elder

We study general nilpotent algebras. The results obtained are new even for the classical algebras, such as associative or Lie algebras. We single out certain generic properties of finite-dimensional algebras, mostly over infinite fields.…

Rings and Algebras · Mathematics 2024-06-25 Yuri Bahturin , Alexander Olshanskii

In SGA 2, Grothendieck conjectures that the \'etale fundamental group of the punctured spectrum of a complete noetherian local domain of dimension at least two with algebraically closed residue field is topologically finitely generated. In…

Number Theory · Mathematics 2023-07-21 Takashi Suzuki

We prove that every finitely generated, residually finite group $G$ embeds into a finitely generated perfect branch group $\Gamma$ such that many properties of $G$ are preserved under this embedding. Among those are the properties of being…

Group Theory · Mathematics 2024-03-06 Steffen Kionke , Eduard Schesler

A measure preserving action of a countably infinite group \Gamma is called totally ergodic if every infinite subgroup of \Gamma acts ergodically. For example, all mixing and mildly mixing actions are totally ergodic. This note shows that if…

Dynamical Systems · Mathematics 2012-08-06 Robin Tucker-Drob

We provide an estimate of the amenable category of oriented closed connected complete affine manifolds whose fundamental group contains an infinite amenable normal subgroup. As an application we show that all such manifolds have zero…

Geometric Topology · Mathematics 2025-02-11 Alberto Casali , Marco Moraschini

We prove, for various important classes of Mealy automata, that almost all generated groups have an element of infinite order. In certain cases, it also implies other results such as exponential growth.

Formal Languages and Automata Theory · Computer Science 2019-03-28 Thibault Godin

A definable set $X$ in the first-order language of rings defines a family of random vectors: for each finite field $\mathbb{F}_q$, let the distribution be supported and uniform on the $\mathbb{F}_q$-rational points of $X$. We employ results…

Information Theory · Computer Science 2025-02-28 Tobias Boege

We show that free Burnside groups of sufficiently large odd exponent are non--amenable in a certain strong sense, more precisely, their left regular representations are isolated from the trivial representation uniformly on finite generating…

Group Theory · Mathematics 2007-05-23 D. V. Osin

We will give an example of a branch group $G$ that has exponential growth but does not contain any non-abelian free subgroups. This answers question 16 from \cite{Bartholdi} positively. The proof demonstrates how to construct a non-trivial…

Group Theory · Mathematics 2012-09-25 Elisabeth Fink

We prove that all definable pre-orders are atomic, in a finitely generated free algebra of a discriminator variety of finite similarity type which is generated by its finite members.

Logic · Mathematics 2016-06-27 H. Andréka , I. Németi

This paper studies effective separability for subgroups of finitely generated nilpotent groups and more broadly effective subgroup separability of finitely generated nilpotent groups. We provide upper and lower bounds that are polynomial…

Group Theory · Mathematics 2018-10-02 Jonas Deré , Mark Pengitore

It was proved that whenever $\mathbb{N}$ is partitioned into finitely many cells, one cell must contain arbitrary length arithmetic and geometric progression nicely intertwined, so that one cell must be rich in the sense of containing…

Combinatorics · Mathematics 2012-01-24 Dibyendu De , Ram Krishna Paul