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There has been a great deal of attention recently to graphs whose vertex set is a group, defined using the group structure. (The commuting graph, where two elements are joined if they commute, is the oldest and most famous example.) The…

Combinatorics · Mathematics 2026-02-03 Peter J. Cameron

We investigate structural implications arising from the condition that a given directed graph does not interpret, in the sense of primitive positive interpretation with parameters or orbits, every finite structure. Our results generalize…

Logic in Computer Science · Computer Science 2023-02-24 Libor Barto , Bertalan Bodor , Marcin Kozik , Antoine Mottet , Michael Pinsker

Random intersection graphs model networks with communities, assuming an underlying bipartite structure of groups and individuals, where these groups may overlap. Group memberships are generated through the bipartite configuration model.…

Probability · Mathematics 2026-01-14 Remco van der Hofstad , Julia Komjathy , Viktoria Vadon

These notes concern aspects of various graphs whose vertex set is a group $G$ and whose edges reflect group structure in some way (so that they are invariant under the action of the automorphism group of $G$). The graphs I will discuss are…

Group Theory · Mathematics 2021-03-29 Peter J. Cameron

Statistical inference for exponential-family models of random graphs with dependent edges is challenging. We stress the importance of additional structure and show that additional structure facilitates statistical inference. A simple…

Statistics Theory · Mathematics 2020-03-13 Michael Schweinberger , Jonathan Stewart

This paper introduces a notion of presentation for locally inverse semigroups and develops a graph structure to describe the elements of locally inverse semigroups given by these presentations. These graphs will have a role similar to the…

Group Theory · Mathematics 2021-12-22 Luís Oliveira

We study how the problem of observables is fully resolved for background independent theories defined on finite graphs. We argue the correct analogue of coordinate independence is the invariance under changes of graph labels, a kind of…

General Relativity and Quantum Cosmology · Physics 2025-08-05 Emil Broukal , Andrea Di Biagio , Eugenio Bianchi , Marios Christodoulou

This paper studies the classes of semigoups and monoids with context-free and deterministic context-free word problem. First, some examples are exhibited to clarify the relationship between these classes and their connection with the…

Group Theory · Mathematics 2019-03-26 Tara Brough , Alan J. Cain , Markus Pfeiffer

The physics of complex systems stands to greatly benefit from the qualitative changes in data availability and advances in data-driven computational methods. Many of these systems can be represented by interacting degrees of freedom on…

Statistical Mechanics · Physics 2024-11-27 Doruk Efe Gökmen , Sounak Biswas , Sebastian D. Huber , Zohar Ringel , Felix Flicker , Maciej Koch-Janusz

We establish combinatorial characterizations of virtually torsion-free and virtually free groups using the canonical graph decomposition theory in \cite{DJKK22}. Our main results show that a finitely presented, residually finite group…

Group Theory · Mathematics 2026-03-06 R. Köhl , M. Reza Salarian

In a previous paper [1] [MR4101040], we initiated a systematic study of semihypergroups and had a thorough discussion about some important analytic and algebraic objects associated to this class of objects. In this paper, we investigate…

Functional Analysis · Mathematics 2022-09-30 Choiti Bandyopadhyay

We study subsets $E$ of finitely generated groups where the set of all words over a given finite generating set that lie in $E$ forms a context-free language. We call these sets recognisably context-free. They are invariant of the choice of…

Group Theory · Mathematics 2024-05-01 Alex Levine

We study contraction groups for automorphisms of totally disconnected locally compcat groups using the scale of the automorphism as a tool. The contraction group is shown to be unbounded when the inverse automorphism has non-trivial scale…

Group Theory · Mathematics 2007-05-23 Udo Baumgartner , George A. Willis

Based on methods of structural convergence we provide a unifying view of local-global convergence, fitting to model theory and analysis. The general approach outlined here provides a possibility to extend the theory of local-global…

Combinatorics · Mathematics 2018-10-18 Jaroslav Nesetril , Patrice Ossona de Mendez

We introduce an algebraic structure for studying state-independent contextuality arguments, a key form of quantum non-classicality exemplified by the well-known Peres-Mermin magic square, and used as a source of quantum advantage. We…

Quantum Physics · Physics 2026-03-16 Samson Abramsky , Serban-Ion Cercelescu , Carmen-Maria Constantin

From the point of view of discrete geometry, the class of locally finite transitive graphs is a wide and important one. The subclass of Cayley graphs is of particular interest, as testifies the development of geometric group theory. Recall…

Combinatorics · Mathematics 2016-12-06 Sébastien Martineau

We establish a combination theorem for parafree groups. These groups were introduced by Baumslag in the sixties. One of the current motivations for a better understanding of their structure is that they show up naturally in connection with…

Group Theory · Mathematics 2024-03-04 Andrei Jaikin-Zapirain , Ismael Morales

Understanding the structure of a graph along with the structure of its subgraphs is important for several problems in graph theory. Two examples are the Reconstruction Conjecture and isomorph-free generation. This paper raises the question…

Combinatorics · Mathematics 2009-09-18 Stephen G. Hartke , Hannah Kolb , Jared Nishikawa , Derrick Stolee

This paper, and its companion [BCV24], are devoted to a negative resolution of the Aldous--Lyons Conjecture [AL07, Ald07]. This conjecture, originated in probability theory, is well known (cf. [Gel18]) to be equivalent to the statement that…

Group Theory · Mathematics 2024-08-02 Lewis Bowen , Michael Chapman , Alexander Lubotzky , Thomas Vidick

We investigate the structure of connected graphs, not necessarily locally finite, with infinitely many ends. On the one hand we study end-transitive such graphs and on the other hand we study such graphs with the property that the…

Combinatorics · Mathematics 2010-03-19 Matthias Hamann