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Recent research in coarse geometry revealed similarities between certain concepts of analysis, large scale geometry, and topology. Property A of G.Yu is the coarse analog of amenability for groups and its generalization (exact spaces) was…

Metric Geometry · Mathematics 2014-01-07 M. Cencelj , J. Dydak , A. Vavpetič

We study the topological structure and the topological dynamics of groups of homeomorphisms of scattered spaces. For a large class of them (including the homeomorphism group of any ordinal space or of any locally compact scattered space),…

Group Theory · Mathematics 2020-12-01 Maxime Gheysens

In this paper, we first propose the concept of Rota-Baxter family $\Omega$-associative conformal algebras, then we study the cohomology theory of Rota-Baxter family $\Omega$-associative conformal algebras of any weight and justify it by…

Rings and Algebras · Mathematics 2023-01-31 Yuanyuan Zhang , Jun Zhao , Genqiang Liu

We define a 2-category structure (Pre-Orb) on the category of reduced complex orbifold atlases. We construct a 2-functor F from (Pre-Orb) to the 2-category (Grp) of proper \'etale effective groupoid objects over the complex manifolds. Both…

Algebraic Topology · Mathematics 2010-10-05 Matteo Tommasini

The purpose of this paper is to study the structure and the algebraic varieties of Hom-associative algebras. We give characterize multiplicative simple Hom-associative algebras and show some examples deforming the $2\times 2$-matrix algebra…

Rings and Algebras · Mathematics 2019-06-13 Ahmed Zahari , Abdenacer Makhlouf

Moore characterized the amenability of automorphism groups of countable ultrahomogeneous structures by a Ramsey-type property. We extend this result to automorphism groups of metric Fra\"iss\'e structures, which encompass all Polish groups.…

Logic · Mathematics 2013-09-06 Adriane Kaïchouh

We show that the group of type-preserving automorphisms of any irreducible semi-regular thick right-angled building is abstractly simple. When the building is locally finite, this gives a large family of compactly generated (abstractly)…

Group Theory · Mathematics 2014-05-15 Pierre-Emmanuel Caprace

We show that the automorphism groups of certain countable structures obtained using the Hrushovski amalgamation method are simple groups. The structures we consider are the 'uncollapsed' structures of infinite Morley rank obtained by the ab…

Logic · Mathematics 2015-09-03 David M. Evans , Zaniar Ghadernezhad , Katrin Tent

A first-order structure $\mathfrak{A}$ is called monadically stable iff every expansion of $\mathfrak{A}$ by unary predicates is stable. In this article we give a classification of the class $\mathcal{M}$ of $\omega$-categorical monadically…

Logic · Mathematics 2020-11-18 Bertalan Bodor

We classify compact manifolds of dimension three equipped with a path structure and a fixed contact form (which we refer to as a strict path structure) under the hypothesis that their automorphism group is non-compact. We use a Cartan…

Differential Geometry · Mathematics 2023-03-09 Elisha Falbel , Martin Mion-Mouton , Jose Miguel Veloso

We analyze definably compact groups in o-minimal expansions of ordered groups as a combination of semi-linear groups and groups definable in o-minimal expansions of real closed fields. The analysis involves structure theorems about their…

Logic · Mathematics 2012-02-28 Pantelis Eleftheriou , Ya'acov Peterzil

We build a concrete and natural model for the strict 2-category of orbifolds. In particular we prove that if one localizes the 2-category of proper etale Lie groupoids at a class of 1-arrows that we call "covers", then the strict 2-category…

Differential Geometry · Mathematics 2010-09-02 Eugene Lerman

Ultrahomogeneity and $\omega$-categoricity are two central concepts arising from model theory, with strong connections with oligomorphic permutation groups and quantifier elimination. In particular, both are conditions on the automorphism…

Logic · Mathematics 2026-03-30 Thomas Quinn-Gregson

Decomposable ordered structures were introduced in \cite{OnSt} to develop a general framework to study `finite-dimensional' totally ordered structures. This paper continues this work to include decomposable structures on which a ordered…

Logic · Mathematics 2014-02-27 Eliana Barriga , Alf Onshuus , Charles Steinhorn

The aim of this paper is to study co-prolongations of central extensions. We construct the obstruction theory for co-prolongations and classify the equivalence classes of these by kernels of a homomorphisms between 2-dimensional cohomology…

Group Theory · Mathematics 2013-09-13 Nguyen Tien Quang , Doan Trong Tuyen , Nguyen Thi Thu Thuy

We initiate the study of analogues of symmetric spaces for the family of finite dihedral groups. In particular, we investigate the structure of the automorphism group, characterize the involutions of the automorphism group, and determine…

We present a diagram surveying equivalence or strict implication for properties of different nature (algebraic, model theoretic, topological, etc.) about groups definable in o-minimal structures. All results are well-known and an extensive…

Logic · Mathematics 2020-10-29 Annalisa Conversano

We study amenability of affine algebras (based on the notion of almost-invariant finite-dimensional subspace), and apply it to algebras associated with finitely generated groups. We show that a group G is amenable if and only if its group…

Group Theory · Mathematics 2009-11-27 Laurent Bartholdi

We study the automorphism group of an idempotent evolution algebra, show that any finite group can be the automorphism group of an evolution algebra, and describe certain evolution algebras with given automorphism groups. In particular, we…

Rings and Algebras · Mathematics 2022-02-15 Songpon Sriwongsa , Yi Ming Zou

Characteristic class relations in Dolbeault cohomology follow from the existence of a holomorphic geometric structure (for example, holomorphic conformal structures, holomorphic Engel distributions, holomorphic projective connections, and…

Differential Geometry · Mathematics 2025-09-29 Benjamin McKay