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The group described in this paper appeared while studying fundamental groups of complements of branch curves. It turned out that a certain quotient of the braid group acts on those fundamental groups and studying this action is essential…

alg-geom · Mathematics 2016-08-30 Mina Teicher

We define the braid groups of a two-dimensional orbifold and introduce conventions for drawing braid pictures. We use these to realize the Artin groups associated to the spherical Coxeter diagrams A_n, B_n=C_n and D_n and the affine…

Geometric Topology · Mathematics 2007-05-23 Daniel Allcock

Motivated by recent activity in low-dimensional topology, we provide a new criterion for left-orderability of a group under the assumption that the group is circularly-orderable: A group $G$ is left-orderable if and only if $G \times…

Group Theory · Mathematics 2020-10-27 Jason Bell , Adam Clay , Tyrone Ghaswala

We introduce a new method of detecting when the fundamental group of a Dehn surgery on a knot admits a left-ordering, a method which is particularly useful for 2-bridge knots. As an illustration of this method, we show that all Dehn…

Geometric Topology · Mathematics 2023-07-04 Ollie Thakar

Let $\Gamma$ be a finite connected graph. The (unlabelled) configuration space $UC^n \Gamma$ of $n$ points on $\Gamma$ is the space of $n$-element subsets of $\Gamma$. The $n$-strand braid group of $\Gamma$, denoted $B_n\Gamma$, is the…

Group Theory · Mathematics 2010-04-05 Daniel Farley , Lucas Sabalka

The n-string braid group of a graph X is defined as the fundamental group of the n-point configuration space of the space X. This configuration space is a finite dimensional aspherical space. A. Abrams and R. Ghrist have conjectured that…

Geometric Topology · Mathematics 2007-05-23 Frank Connolly , Margaret Doig

We prove that every right-angled Artin group occurs as a finite-index subgroup of the outer automorphism group of another right-angled Artin group. We furthermore show that the latter group can be chosen in such a way that the quotient is…

Group Theory · Mathematics 2024-03-14 Manuel Wiedmer

Unifying various constructions of quandles including Coxeter quandles, free quandles, knot quandles of prime knots and Dehn quandles of orientable surfaces, we introduce Dehn quandles of groups with respect to their subsets. It turns out…

Geometric Topology · Mathematics 2024-06-11 Neeraj K. Dhanwani , Hitesh Raundal , Mahender Singh

Dehn twists around simple closed curves in oriented surfaces satisfy the braid relations. This gives rise to a group theoretic from the braid group to the mapping class group. We prove here that this map is trivial in stable homology with…

Algebraic Topology · Mathematics 2007-05-23 Yongjin Song , Ulrike Tillmann

We obtain new presentations for the imprimitive complex reflection groups of type $(de,e,r)$ and their braid groups $B(de,e,r)$ for $d,r \ge 2$. Diagrams for these presentations are proposed. The presentations have much in common with…

Group Theory · Mathematics 2015-01-27 Ruth Corran , Eon-Kyung Lee , Sang-Jin Lee

We study some properties of the dynamical realization of isolated left orders of a countable group G. We show that the dynamical realization admits a unique minimal set provided G is not infinite cyclic. We show that convex subgroup of an…

Group Theory · Mathematics 2018-11-28 Shigenori Matsumoto

Right-angled Artin groups and their subgroups are of great interest because of their geometric, combinatorial and algorithmic properties. It is convenient to define these groups using finite simplicial graphs. The isomorphism type of the…

Group Theory · Mathematics 2023-12-15 Priyavrat Deshpande , Mallika Roy

This paper initiates the study of circular orderability of $3$-manifold groups, motivated by the L-space conjecture. We show that a compact, connected, $\mathbb{P}^2$-irreducible $3$-manifold has a circularly orderable fundamental group if…

Geometric Topology · Mathematics 2025-05-21 Idrissa Ba , Adam Clay

We investigate a group $B\_\bullet$ that includes Artin's braid group $B\_\infty$ and Thompson's group $F$. The elements of $B\_\bullet$ are represented by braids diagrams in which the distances between the strands are not uniform and,…

Group Theory · Mathematics 2007-05-23 Patrick Dehornoy

We derive a lower bound on the size of finite non-cyclic quotients of the braid group that is superexponential in the number of strands. We also derive a similar lower bound for nontrivial finite quotients of the commutator subgroup of the…

Geometric Topology · Mathematics 2019-12-12 Alice Chudnovsky , Kevin Kordek , Qiao Li , Caleb Partin

The present article continues the study of median groups initiated in [6, 9, 10]. Some classes of median groups are introduced and investigated with a stress upon the class of the so called A-groups which contains as remarkable subclasses…

Group Theory · Mathematics 2009-09-23 Şerban A. Basarab

In the note we prove that all composition factors of a finite group possessing a Carter subgroup of odd order either are abelain, or are isomorphic to $L_2(3^{2n+1})$.

Group Theory · Mathematics 2015-04-01 E. P. Vdovin

The relationships between braid ordering and the geometry of its closure is studied. We prove that if an essential closed surface $F$ in the complements of closed braid has relatively small genus with respect to the Dehornoy floor of the…

Geometric Topology · Mathematics 2011-07-25 Tetsuya Ito

The Tits Conjecture, proved by Crisp and Paris, states that squares of the standard generators of any Artin group generate an obvious right-angled Artin subgroup. We consider a larger set of elements consisting of all the centers of the…

Group Theory · Mathematics 2022-01-19 Kasia Jankiewicz , Kevin Schreve

The congruence subgroups of braid groups arise from a congruence condition on the integral Burau representation $B_n \to \operatorname{GL}_{n}(\mathbb Z)$. We find the image of such congruence subgroups in $\operatorname{GL}_{n}(\mathbb…

Group Theory · Mathematics 2023-06-13 Wade Bloomquist , Peter Patzt , Nancy Scherich