A subscription is required to access this article.
For any surface of infinite topological type, we study the Torelli subgroup of the mapping class group MCG, whose elements are those mapping classes that act trivially on the homology of . Our first result asserts that is topologically generated by the subgroup of MCG consisting of those elements in the Torelli group which have compact support. Next, we prove the abstract commensurator group of coincides with MCG. This extends the results for finite-type surfaces [9, 6, 7, 16] to the setting of infinite-type surfaces.
Cite this article
Javier Aramayona, Tyrone Ghaswala, Autumn E. Kent, Alan McLeay, Jing Tao, Rebecca R. Winarski, Big Torelli groups: generation and commensuration. Groups Geom. Dyn. 13 (2019), no. 4, pp. 1373–1399