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Related papers: Recent progress in subset combinatorics of groups

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Let $G$ be a group and let $X$ be a transitive $G$-space. We classify the subsets of $X$ with respect to a translation invariant ideal $\mathcal{J}$ in the Boolean algebra of all subsets of $X$, introduce and apply the relative…

Group Theory · Mathematics 2014-09-26 Igor Protasov , Sergii Slobodianiuk

We explore the Borel complexity of some basic families of subsets of a countable group (large, small, thin, sparse and other) defined by the size of their elements. Applying the obtained results to the Stone-\v{C}ech compactification $\beta…

General Topology · Mathematics 2017-03-02 Igor Protasov , Taras Banakh , Ksenia Protasova

Let $G$ be a group, $\beta G$ is the Stone-$\check{C}$ech compactification of $\beta G$ endowed with the structure of a right topological semigroup, $G^*=\beta G\setminus G$. Given any subset $A$ of $G$ and $p\in G^*$, we define the…

Group Theory · Mathematics 2013-08-08 I. Protasov , S. Slobodianiuk

There is a long history of studying Ramsey theory using the algebraic structure of the Stone-\v{C}ech compactification of discrete semigroup. It has been shown that various Ramsey theoretic structures are contained in different algebraic…

General Topology · Mathematics 2021-08-12 Dibyendu De , Pintu Debnath , Sayan Goswami

For a discrete group $G$, we use the natural correspondence between ideals in the Boolean algebra $ \mathcal{P}_G$ of subsets of $G$ and closed subsets in the Stone-$\check{C}$ech compactifi-cation $\beta G$ as a right topological semigroup…

General Topology · Mathematics 2017-04-11 Igor Protasov , Ksenia Protasova

This is a survey of recent progress in several areas of combinatorial algebra. We consider combinatorial problems about free groups, polynomial algebras, free associative and Lie algebras. Our main idea is to study automorphisms and, more…

Group Theory · Mathematics 2016-09-07 Alexander A. Mikhalev , Vladimir Shpilrain , Jie-Tai Yu

In this talk we introduce several topics in combinatorial number theory which are related to groups; the topics include combinatorial aspects of covers of groups by cosets, and also restricted sumsets and zero-sum problems on abelian…

Group Theory · Mathematics 2007-05-23 Zhi-Wei Sun

Given a discrete group $G$, we identify the Stone-$\check C$ech compactification $\beta G$ with the set of all ultrafilters on $G$ and put $G^\ast =\beta G\setminus G$. The action $G$ on $G$ by the conjugations $(g,x)\mapsto g^{-1}xg$…

Group Theory · Mathematics 2020-07-03 Igor Protasov , Ksenia Protasova

We develop in this paper general techniques to analyze local combinatorial structures in product sets of two subsets of a countable group which are "large" with respect to certain classes of (not necessarily invariant) means on the group.…

Dynamical Systems · Mathematics 2016-02-22 MIchael Björklund , Alexander Fish

There is a long history of studying Ramsey theory using the algebraic structure of Stone-Cech compactification of discrete semigroup. It has been shown that various Ramsey theoretic structures are contained in different algebraic large…

Dynamical Systems · Mathematics 2020-05-12 Pintu Debnath , Sayan Goswami

Let $G$ be a group, $\mathcal{P}_G$ be the family of all subsets of $G$. For a subset $A\subseteq G$, we put $\Delta(A)=\{g\in G:|gA\cap A|=\infty\}$. The mapping $\Delta:\mathcal{P}_G\rightarrow\mathcal{P}_G$, $A\mapsto\Delta(A)$, is…

Combinatorics · Mathematics 2012-10-03 Igor V. Protasov

We prove additive and multiplicative partition theorems, obtaining combinatorial results for p-quasicyclic groups, where p is a prime number. We also get density results for p-quasicyclic groups via left F{\o}lner sequences of non-empty…

Combinatorics · Mathematics 2014-08-19 Andreas Koutsogiannis

This text surveys classical and recent results in the field of amenability of groups, from a combinatorial standpoint. It has served as the support of courses at the University of G\"ottingen and the \'Ecole Normale Sup\'erieure. The goals…

Group Theory · Mathematics 2017-05-12 Laurent Bartholdi

This survey article is devoted to general results in combinatorial enumeration. The first part surveys results on growth of hereditary properties of combinatorial structures. These include permutations, ordered and unordered graphs and…

Combinatorics · Mathematics 2008-04-01 Martin Klazar

In this paper we will systematically study the preservation of the notion of largeness of sets, arises from the algebraic structure of Stone-Cech compactification, under homomorphism and difference group. Some of these results were studied…

Combinatorics · Mathematics 2020-08-18 Sayan Goswami , Subhajit Jana

After defining continuous extensions of binary relations on the set N of natural numbers to its Stone-Cech compactification \beta N, we establish some results about one of such extensions. This provides us with one possible divisibility…

General Topology · Mathematics 2014-10-27 Boris Šobot

The paper is an overview of recent results on algebraic structures (semigroups, groupoids, algebras, inverse semigroups, and groups) associated with objects with a rich set of partial symmetries. We discuss etale groupoids and inverse…

Operator Algebras · Mathematics 2025-09-09 Volodymyr Nekrashevych

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

In this survey paper we discuss some recent results and related open questions in additive combinatorics, in particular, questions about sumsets in finite abelian groups.

Number Theory · Mathematics 2022-11-04 Bela Bajnok

Let $\Gamma$ be a discrete group. To every ideal in $\ell^{\infty}(\G)$ we associate a C$^*$-algebra completion of the group ring that encapsulates the unitary representations with matrix coefficients belonging to the ideal. The general…

Operator Algebras · Mathematics 2014-02-26 Nathanial P. Brown , Erik Guentner
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