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We prove that the infinite family of asymptotic mapping class groups of surfaces of defined by Funar--Kapoudjian and Aramayona--Funar are of type $F_\infty$, thus answering questions of Funar-Kapoudjian-Sergiescu and Aramayona-Vlamis. As it…

Geometric Topology · Mathematics 2024-07-10 Javier Aramayona , Kai-Uwe Bux , Jonas Flechsig , Nansen Petrosyan , Xiaolei Wu

A normal subgroup of the (extended) mapping class group of a surface is said to be geometric if its automorphism group is the mapping class group. We prove that in the case of the Cantor tree surface, every normal subgroup is geometric. We…

Group Theory · Mathematics 2020-02-18 Alan McLeay

For every $n\ge 2$, the {\em surface Houghton group} $\mathcal B_n$ is defined as the asymptotically rigid mapping class group of a surface with exactly $n$ ends, all of them non-planar. The groups $\mathcal B_n$ are analogous to, and in…

Geometric Topology · Mathematics 2023-04-11 Javier Aramayona , Kai-Uwe Bux , Heejoung Kim , Christopher J. Leininger

We prove that the mapping class group of the one-holed Cantor tree surface is acyclic. This in turn determines the homology of the mapping class group of the once-punctured Cantor tree surface (i.e. the plane minus a Cantor set), in…

Geometric Topology · Mathematics 2025-01-07 Martin Palmer , Xiaolei Wu

We introduce subgroups ${\mathcal{B}}_g< {\mathcal H}_g$ of the mapping class group $Mod(\Sigma_g)$ of a closed surface of genus $g \ge 0$ with a Cantor set removed, which are extensions of Thompson's group $V$ by a direct limit of mapping…

Geometric Topology · Mathematics 2021-05-21 Javier Aramayona , Louis Funar

The braided Thompson group $\mathcal B$ is an asymptotic mapping class group of a sphere punctured along the standard Cantor set, endowed with a rigid structure. Inspired from the case of finite type surfaces we consider a Hatcher-Thurston…

Geometric Topology · Mathematics 2019-01-25 Louis Funar , Maxime Nguyen

We study the bounded cohomology of certain groups acting on the Cantor set. More specifically, we consider the full group of homeomorphisms of the Cantor set as well as Thompson's group $V$. We prove that both of these groups are boundedly…

Group Theory · Mathematics 2022-10-04 Konstantin Andritsch

This article is dedicated to the study of asymptotically rigid mapping class groups of infinitely-punctured surfaces obtained by thickening planar trees. Such groups include the braided Ptolemy-Thompson groups $T^\sharp,T^\ast$ introduced…

Group Theory · Mathematics 2022-08-17 Anthony Genevois , Anne Lonjou , Christian Urech

The surface Houghton groups $\mathcal{H}_{n}$ are a family of groups generalizing Houghton groups $H_n$, which are constructed as asymptotically rigid mapping class groups. We give a complete computation of the BNSR-invariants…

Geometric Topology · Mathematics 2025-11-26 Noah Torgerson , Jeremy West

The aim of this paper is to introduce a group containing the mapping class groups of all genus zero surfaces. Roughly speaking, such a group is intended to be a discrete analogue of the diffeomorphism group of the circle. One defines indeed…

Geometric Topology · Mathematics 2007-05-23 Louis Funar , Christophe Kapoudjian

We show that the homeomorphism group of a surface without boundary does not admit a Hausdorff group topology strictly coarser than the compact-open topology. In combination with known automatic continuity results, this implies that the…

Geometric Topology · Mathematics 2022-11-08 J. de la Nuez González

In this paper, we give presentations of the mapping class groups of marked surfaces stabilizing boundaries for any genus. Note that in the existing works, the mapping class groups of marked surfaces were the isotopy classes of…

Geometric Topology · Mathematics 2023-07-31 Jinlei Dong , Fang Li

We consider finite-sheeted, regular, possibly branched covering spaces of compact surfaces with boundary and the associated liftable and symmetric mapping class groups. In particular, we classify when either of these subgroups coincides…

Geometric Topology · Mathematics 2020-03-11 Tyrone Ghaswala , Alan McLeay

We observe that, for each positive integer n > 2, each of the Artin groups of finite type A_n, B_n=C_n, and affine type \tilde A_{n-1} and \tilde C_{n-1} is a central extension of a finite index subgroup of the mapping class group of the…

Group Theory · Mathematics 2007-05-23 Ruth Charney , John Crisp

In this note, we prove that the compactly supported mapping class group of a surface containing a genus $3$ subsurface has no realization as a subgroup of the homeomorphism group. We also prove that for certain surfaces with order $6$…

Geometric Topology · Mathematics 2022-09-07 Lei Chen , Yan Mary He

We show that the pure mapping class group is uniformly perfect for a certain class of infinite type surfaces with noncompact boundary components. We then combine this result with recent work in the remaining cases to give a complete…

Geometric Topology · Mathematics 2023-09-13 Ryan Dickmann

Suppose $G$ is a locally solid lattice group. It is known that there are non-equivalent classes of bounded homomorphisms on $G$ which have topological structures. In this paper, our attempt is to assign lattice structures on them. More…

Functional Analysis · Mathematics 2019-09-06 Omid Zabeti

Combinatorial aspects of the Torelli-Johnson-Morita theory of surface automorphisms are extended to certain subgroups of the mapping class groups. These subgroups are defined relative to a specified homomorphism from the fundamental group…

Geometric Topology · Mathematics 2012-01-19 Yusuke Kuno , R. C. Penner , Vladimir Turaev

We study a quasimorphism, which we call the Dehn twist coefficient (DTC), from the mapping class group of a surface (with a chosen compact boundary component) that generalizes the well-studied fractional Dehn twist coefficient (FDTC) to…

Geometric Topology · Mathematics 2025-07-15 Peter Feller , Diana Hubbard , Hannah Turner

Given an oriented surface of positive genus with finitely many punctures, we classify the finite orbits of the mapping class group action on the moduli space of semisimple complex special linear two dimensional representations of the…

Geometric Topology · Mathematics 2022-06-29 Indranil Biswas , Subhojoy Gupta , Mahan Mj , Junho Peter Whang
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