WWPD elements of big mapping class groups
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.
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