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The objective of this series is to study metric geometric properties of (coarse) disjoint unions of amenable Cayley graphs. We employ the Cayley topology and observe connections between large scale structure of metric spaces and group…

Group Theory · Mathematics 2019-03-13 Masato Mimura , Hiroki Sako

We investigate near-factorizations of nonabelian groups, concentrating on dihedral groups. We show that some known constructions of near-factorizations in dihedral groups yield equivalent near-factorizations. In fact, there are very few…

Group Theory · Mathematics 2025-01-29 Donald L. Kreher , Maura B. Paterson , Douglas R. Stinson

This study focuses on exploring the use of local interpretability methods for explaining time series clustering models. Many of the state-of-the-art clustering models are not directly explainable. To provide explanations for these…

Machine Learning · Computer Science 2022-08-03 Ozan Ozyegen , Nicholas Prayogo , Mucahit Cevik , Ayse Basar

This is a translation. I have added translations for (possibly) outdated definitions in an appendix at the end. In this paper, we define distributive groups and show some properties of them. We then concern ourselves with the homogeinity of…

Group Theory · Mathematics 2026-05-19 C. Burstin , W. Mayer

Computer based techniques for recognizing finitely presented groups are quite powerful. Tools available for this purpose are outlined. They are available both in stand-alone programs and in more comprehensive systems. A general…

Group Theory · Mathematics 2008-02-03 George Havas , Edmund F. Robertson

We answer a question of Downey and Kurtz on left-orderable groups by showing that there is a computable left-orderable group which is not classically isomorphic to a computable group with a computable left-order.

Logic · Mathematics 2016-11-21 Matthew Harrison-Trainor

We prolonge the list of C*-algebras for which all extensions by any stable separable C*-algebra are semi-invertible. In particular, we handle certain amalgamations, both of C*-algebras and of groups. Concerning groups we consider both…

Operator Algebras · Mathematics 2010-05-13 Vladimir Manuilov , Klaus Thomsen

Every countable group that does not contain a finitely generated subgroup of exponential growth imbeds in a finitely generated group of subexponential growth. This produces in particular the first examples of groups of subexponential growth…

Group Theory · Mathematics 2015-01-29 Laurent Bartholdi , Anna Erschler

We show that various aspects of k-automatic sequences -- such as having an unbordered factor of length n -- are both decidable and effectively enumerable. As a consequence it follows that many related sequences are either k-automatic or…

Formal Languages and Automata Theory · Computer Science 2011-10-14 Emilie Charlier , Narad Rampersad , Jeffrey Shallit

While there is a well-established notion of what a computable ordinal is, the question which functions on the countable ordinals ought to be computable has received less attention so far. We propose a notion of computability on the space of…

Logic in Computer Science · Computer Science 2017-04-11 Arno Pauly

Although there is a somewhat standard formalization of computability on countable sets given by Turing machines, the same cannot be said about uncountable sets. Among the approaches to define computability in these sets, order-theoretic…

Logic in Computer Science · Computer Science 2022-09-07 Pedro Hack , Daniel A. Braun , Sebastian Gottwald

In this paper, we study a family of finitely generated elementary amenable iet-groups. These groups are generated by finitely many rationals iets and rotations. For them, we state criteria for not virtual nilpotency or solvability, and we…

Group Theory · Mathematics 2026-02-02 Nancy Guelman , Isabelle Liousse

We show that Morley's theorem on the number of countable models of a countable first-order theory becomes an undecidable statement when extended to second-order logic. More generally, we calculate the number of equivalence classes of…

Logic · Mathematics 2023-07-06 Christopher J. Eagle , Clovis Hamel , Sandra Müller , Franklin D. Tall

Many groups possess highly symmetric generating sets that are naturally endowed with an underlying combinatorial structure. Such generating sets can prove to be extremely useful both theoretically in providing new existence proofs for…

Group Theory · Mathematics 2010-04-22 Ben Fairbairn

We consider the amenability of groupoids $G$ equipped with a group valued cocycle $c:G\to Q$ with amenable kernel $c^{-1}(e)$. We prove a general result which implies, in particular, that $G$ is amenable whenever $Q$ is amenable and if…

Operator Algebras · Mathematics 2015-03-18 Jean N. Renault , Dana P. Williams

We prove that there is a unique graph with four edges which is the Gruenberg-Kegel graph of a solvable cut group. This contributes to the classification of the Gruenberg-Kegel graphs of solvable cut groups initiated in [A. B\"achle, A.…

Group Theory · Mathematics 2026-04-03 Sara C. Debón , Diego García-Lucas , Ángel del Río

A classification is given for factorizations of almost simple groups with at least one factor solvable, and it is then applied to characterize $s$-arc-transitive Cayley graphs of solvable groups, leading to a striking corollary: Except the…

Group Theory · Mathematics 2016-02-29 Cai Heng Li , Binzhou Xia

Sets of desirable gambles constitute a quite general type of uncertainty model with an interesting geometrical interpretation. We give a general discussion of such models and their rationality criteria. We study exchangeability assessments…

Probability · Mathematics 2010-12-10 Gert de Cooman , Erik Quaeghebeur

We develop a semigroup approach to representation theory for pro-Lie groups satisfying suitable amenability conditions. As an application of our approach, we establish a one-to-one correspondence between equivalence classes of unitary…

Representation Theory · Mathematics 2016-06-07 Daniel Beltita , Amel Zergane

We prove that, if a discrete group $G$ is not inner amenable, then the unit group of the ring of operators affiliated with the group von Neumann algebra of $G$ is non-amenable with respect to the topology generated by its rank metric. This…

Operator Algebras · Mathematics 2025-03-04 Friedrich Martin Schneider