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We show a dichotomy for groups of cardinality less than continuum. The number of homomorphisms from the Hawaiian earring group to such a group $G$ is either the cardinality of $G$ in case $G$ is noncommutatively slender, or the number is…

Group Theory · Mathematics 2019-08-13 Samuel M. Corson

Extending a work of Carlen and Lieb, Biane has obtained the optimal hypercontractivity of the $q$-Ornstein-Uhlenbeck semigroup on the $q$-deformation of the free group algebra. In this note, we look for an extension of this result to the…

Operator Algebras · Mathematics 2015-05-19 Hun Hee Lee , Éric Ricard

General arguments of Baumslag and Bieri guarantee that any metabelian group of finite Pr\"ufer rank can be embedded in a metabelian constructible group. Here, we consider the metric behavior of a rich class of examples and analyze the…

Group Theory · Mathematics 2018-03-28 Sean Cleary , Conchita Martínez-Pérez

Topological properties of the free topological group and the free abelian topological group on a space have been thoroughly studied since the 1940s. In this paper, we study the free topological $\mathbb{R}$-vector space $V(X)$ on $X$. We…

General Topology · Mathematics 2021-07-23 Rafael Dahmen , Gábor Lukács

We derive many upper bounds on the submetrizability number and $i$-weight of paratopological groups and topological monoids with open shifts. In particular, we prove that each first countable Hausdorff paratopological group is submetrizable…

General Topology · Mathematics 2016-02-19 Taras Banakh , Alex Ravsky

We develop a new criterion to tell if a group $G$ has the maximal gap of $1/2$ in stable commutator length (scl). For amalgamated free products $G = A \star_C B$ we show that every element $g$ in the commutator subgroup of $G$ which does…

Geometric Topology · Mathematics 2018-09-17 Nicolaus Heuer

We study the free (associative, non-commutative) Baxter algebra on one generator. The first explicit description of this object is due to Ebrahimi-Fard and Guo. We provide an alternative description in terms of a certain class of trees,…

Combinatorics · Mathematics 2007-05-23 Marcelo Aguiar , Walter Moreira

We prove that the reduced group C*-algebras of infinite countable discrete groups having topologically-free extreme boundaries, or more generally groups that satisfy certain combinatorial property including all acylindrically hyperbolic…

Operator Algebras · Mathematics 2026-04-27 Narutaka Ozawa

A binding group theorem is proved in the context of quantifier-free internality to the fixed field in difference-closed fields of characteristic zero. This is articulated as a statement about the birational geometry of isotrivial algebraic…

Logic · Mathematics 2025-11-13 Moshe Kamensky , Rahim Moosa

We prove an analogue of the Baum-Connes conjecture for free orthogonal quantum groups. More precisely, we show that these quantum groups have a $ \gamma $-element and that $ \gamma = 1 $. It follows that free orthogonal quantum groups are $…

Operator Algebras · Mathematics 2011-07-12 Christian Voigt

Free groups have many applications in Algebraic Topology. In this paper I specifically study the finitely generated free groups by using the covering spaces and fundamental groups. By the Van Kampen's theorem, we have a famous fact that the…

Algebraic Topology · Mathematics 2017-06-30 Gongping Niu

We study varieties of certain ordered $\Sigma$-algebras with restricted completeness and continuity properties. We give a general characterization of their free algebras in terms of submonads of the monad of $\Sigma$-coterms. Varieties of…

Logic in Computer Science · Computer Science 2023-06-22 Zoltan Esik , Dexter Kozen

Without assuming the field structure on the additive group of real numbers $\mathbb{R}$ with the usual order $<,$ we explore the fact that every proper subgroup of $\mathbb{R}$ is either closed or dense. This property of subgroups of the…

Number Theory · Mathematics 2014-05-21 Jitender Singh

$\aleph_1$-free groups, abelian groups for which every countable subgroup is free, exhibit a number of interesting algebraic and set-theoretic properties. In this paper, we give a complete proof that the property of being $\aleph_1$-free is…

Group Theory · Mathematics 2021-04-22 Daniel Herden , Alexandra V. Pasi

We present a class of abelian groups that exhibit a high degree of freeness while possessing no non-trivial homomorphisms to a canonical free object. Unlike prior investigations, which primarily focused on torsion-free groups, our work…

Group Theory · Mathematics 2025-11-11 Mohsen Asgharzadeh , Mohammad Golshani , Saharon Shelah

A group is called $\Lambda$-free if it has a free Lyndon length function in an ordered abelian group $\Lambda$, which is equivalent to having a free isometric action on a $\Lambda$-tree. A group has a regular free length function in…

Group Theory · Mathematics 2015-03-13 O. Kharlampovich , A. Myasnikov , D. Serbin

We consider the logic space of countable (enumerated) groups and show that closed subspaces corresponding to some standard classes of groups have (do not have) generic groups. We also discuss the cases of semigroups and associative rings.

Logic · Mathematics 2025-12-03 Aleksander Ivanov , Krzysztof Majcher

We give a definition of some classes of boolean algebras generalizing free boolean algebras; they satisfy a universal property that certain functions extend to homomorphisms. We give a combinatorial property of generating sets of these…

Logic · Mathematics 2011-10-04 Corey Thomas Bruns

We discuss dense embeddings of surface groups and fully residually free groups in topological groups. We show that a compact topological group contains a nonabelian dense free group of finite rank if and only if it contains a dense surface…

Group Theory · Mathematics 2009-03-02 Emmanuel Breuillard , Tsachik Gelander , Juan Souto , Peter Storm

We study limit models in the class of abelian groups with the subgroup relation and in the class of torsion-free abelian groups with the pure subgroup relation. We show: $\textbf{Theorem}$ (1) If $G$ is a limit model of cardinality…

Logic · Mathematics 2019-08-20 Marcos Mazari-Armida