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In this paper we introduce the framed pure braid group on $n$ strands of an oriented surface, a topological generalisation of the pure braid group $P_n$. We give different equivalents definitions for framed pure braid groups and we study…

Geometric Topology · Mathematics 2010-05-31 Paolo Bellingeri , Sylvain Gervais

We consider braids on $m+n$ strands, such that the first $m$ strands are trivially fixed. We denote the set of all such braids by $B_{m,n}$. Via concatenation $B_{m,n}$ acquires a group structure. The objective of this paper is to find a…

Geometric Topology · Mathematics 2016-09-07 Sofia Lambropoulou

The braid groups B_n can be defined as the mapping class group of the n-punctured disc. The Lawrence-Krammer representation of the braid group B_n is the induced action on a certain twisted second homology of the space of unordered pairs of…

Group Theory · Mathematics 2007-05-23 Stephen J. Bigelow

We prove that the knot groups of $6_2$ and $7_6$ are not bi-orderable. These are the only two knot groups up to 7 crossings whose bi-orderability was not known. Our method applies to a very broad class of knots.

Group Theory · Mathematics 2017-06-14 Azer Akhmedov , Cody Martin

Sometime ago, we showed that a pure Artin braid group is not K\"ahler, i.e. it is not the fundamental group of a compact K\"ahler manifold. This used a result of Bressler, Ramachandran and the author that K\"ahler groups cannot be too…

Algebraic Geometry · Mathematics 2020-07-29 Donu Arapura

This paper upbuilds the theoretical framework of orbit braids in $M\times I$ by making use of the orbit configuration space $F_G(M,n)$, which enriches the theory of ordinary braids, where $M$ is a connected topological manifold of dimension…

Algebraic Topology · Mathematics 2019-04-01 Hao Li , Zhi Lü , Fengling Li

We give a sharp lower bound on the size of nonabelian quotients of the surface braid group $B_n(\Sigma_g)$ and classify all quotients that attain the lower bound: Depending on $n$ and $g$, a quotient of minimum order is either a symmetric…

Geometric Topology · Mathematics 2024-12-18 Cindy Tan

Let n\geq 3. We classify the finite groups which are realised as subgroups of the sphere braid group B_n(S^2). Such groups must be of cohomological period 2 or 4. Depending on the value of n, we show that the following are the maximal…

Geometric Topology · Mathematics 2009-04-24 Daciberg Lima Gonçalves , John Guaschi

Results of Perron and Rolfsen imply that untwisted hyperbolic once-punctured torus bundles over the circle have bi-orderable fundamental groups. They do this by showing that the action of the monodromy preserves a "standard" bi-ordering…

Geometric Topology · Mathematics 2023-10-24 Jonathan Johnson , Henry Segerman

We construct several families of embeddings of braid groups into mapping class groups of orientable and non-orientable surfaces and prove that they induce the trivial map in stable homology in the orientable case, but not so in the…

Algebraic Topology · Mathematics 2012-04-20 Carl-Friedrich Bödigheimer , Ulrike Tillmann

We describe the lower algebraic $K$-theory of the integral group ring of both the pure and full braid groups of the real projective plane $\mathbb{R}P^2$ with $3$ strings, as well as that of the integral group ring of the mapping class…

Geometric Topology · Mathematics 2025-09-03 John Guaschi , Daniel Juan-Pineda

We give a complete classification to when a finite group of outer automorphisms preserves a bi-order on a non-abelian free group and bi-orderable surface groups. We also give another new criterion for an outer automorphism of $F_n$ induced…

Group Theory · Mathematics 2026-04-24 Jonathan Johnson , Khanh Le

We consider the braid groups $\mathbf{B}_n(X)$ on finite simplicial complexes $X$, which are generalizations of those on both manifolds and graphs that have been studied already by many authors. We figure out the relationships between…

Geometric Topology · Mathematics 2021-01-11 Byung Hee An , Hyo Won Park

We construct long sequences of braids that are descending with respect to the standard order of braids (``Dehornoy order''), and we deduce that, contrary to all usual algebraic properties of braids, certain simple combinatorial statements…

Logic · Mathematics 2014-02-26 Lorenzo Carlucci , Patrick Dehornoy , Andreas Weiermann

We classify homomorphisms from the braid group on $n$ strands to the pure mapping class group of a nonoriantable surface of genus $g$. For $n\ge 14$ and $g\le 2\lfloor{n/2}\rfloor+1$ every such homomorphism is either cyclic, or it maps…

Geometric Topology · Mathematics 2025-07-18 Michał Stukow , Błażej Szepietowski

We recover the Dehornoy order on the braid group $B_{2g+n}$ from the tracial state on a cluster $C^*$-algebra $\mathbb{A}(S_{g,n})$ associated to the surface $S_{g,n}$ of genus $g$ with $n$ boundary components. It is proved that the space…

Geometric Topology · Mathematics 2025-06-27 Igor Nikolaev

Generalising previous results on classical braid groups by Artin and Lin, we determine the values of m, n $\in$ N for which there exists a surjection between the n-and m-string braid groups of an orientable surface without boundary. This…

Geometric Topology · Mathematics 2023-06-22 Paolo Bellingeri , Daciberg Lima Gonçalves , John Guaschi

We establish a necessary condition that an automorphism of a nontrivial finitely generated bi-orderable group can preserve a bi-ordering: at least one of its eigenvalues, suitably defined, must be real and positive. Applications are given…

Algebraic Topology · Mathematics 2010-05-28 Adam Clay , Dale Rolfsen

The n-strand braid group can be defined as the fundamental group of the configuration space of n unlabeled points in a closed disk based at a configuration where all n points lie in the boundary of the disk. Using this definition, the…

Group Theory · Mathematics 2021-01-06 Michael Dougherty , Jon McCammond , Stefan Witzel

We give sufficient conditions for left- and bi-orderability of fundamental groups of Ore categories in terms of indirect factors, including Thompson groups and many of their generalizations. Besides recovering known results, we prove that…

Group Theory · Mathematics 2025-03-17 Davide Perego , Matteo Tarocchi