Seminar Event Detail


Date:  Thursday, March 22, 2018
Location:  1866 East Hall (3:00 PM to 4:00 PM)

Title:  Right-angled Artin groups as normal subgroups of mapping class groups

Abstract:   Free normal subgroups of mapping class groups abound, by the result of Dahmani, Guirardel, and Osin that the normal closure of high powers of pseudo-Anosovs is free. At the other extreme, if a normal subgroup contains a mapping class supported on too small a subsurface, it can never be isomorphic to a right-angled Artin group, by work of Brendle and Margalit. I will talk about a case right in between: a family of normal subgroups isomorphic to non-free right-angled Artin groups. We also recover, expand, and make constructive the result of Dahmani, Guirardel, and Osin about free normal subgroups. We do this by creating a version of their "windmill" construction tailor-made for the projection complexes introduced by Bestvina, Bromberg, and Fujiwara. This is joint work with Matt Clay and Dan Margalit.


Speaker:  Johanna Mangahas
Institution:  University at Buffalo

Event Organizer:   Nicholas Vlamis


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