Subgroups of the mapping class group and the Gardiner-Masur compactification
摘要
We study the actions of subgroups of the mapping class group on the Gardiner-Masur compactification of Teichmüller space. We characterize the dynamically irreducible and the dynamically reducible subgroups with respect to the actions on the Gardiner-Masur boundary. This is an analogue of the characterization with respect to the actions on the Thurston boundary due to McCarthy-Papadopoulos. And we construct a domain of discontinuity in the Gardiner-Masur compactification for every subgroup. This is an analogue of the domain of discontinuity in the Thurston compactification constructed by McCarthy-Papadopoulos and Kent-Leininger. Moreover, we characterize the convex cocompact subgroups of the mapping class group through their actions on the Gardiner-Masur compactification. This is an analogue of the characterization through the actions on the Thurston compactification due to Kent-Leininger.