English

WWPD elements of big mapping class groups

Group Theory 2020-08-07 v2 Geometric Topology

Abstract

We study mapping class groups of infinite type surfaces with isolated punctures and their actions on the loop graphs introduced by Bavard-Walker. We classify all of the mapping classes in these actions which are loxodromic with a WWPD action on the corresponding loop graph. The WWPD property is a weakening of Bestvina-Fujiwara's weak proper discontinuity and is useful for constructing non-trivial quasimorphisms. We use this classification to give a sufficient criterion for subgroups of big mapping class groups to have infinite-dimensional second bounded cohomology and use this criterion to give simple proofs that certain natural subgroups of big mapping class groups have infinite-dimensional second bounded cohomology.

Keywords

Cite

@article{arxiv.1909.06680,
  title  = {WWPD elements of big mapping class groups},
  author = {Alexander J. Rasmussen},
  journal= {arXiv preprint arXiv:1909.06680},
  year   = {2020}
}

Comments

Final version to appear in Groups, Geometry, and Dynamics

R2 v1 2026-06-23T11:15:27.868Z