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SUMMARY:Maps between mapping class groups and their subgroups - Martin Bri
 dson\, Oxford
DTSTART:20140226T160000Z
DTEND:20140226T170000Z
UID:TALK49555@talks.cam.ac.uk
CONTACT:Ivan Smith
DESCRIPTION:Homomorphisms between mapping class groups are tightly tied to
  the topology of the surface.\nMore strikingly\, perhaps\, maps between re
 latively slender subgroups are also highly constrained. I'll focus\nmainly
  on this second point and describe work with Alexandra Pettet and Juan Sou
 to in which we prove\,\nin particular\, that (except in low genus) the aut
 omorphism group (and abstract commensurator) of each term \nof the Andread
 akis-Johnson filtration is the ambient mapping class group\, and likewise 
 the terms of the \nlower central series of the Torelli group.  
LOCATION:MR13
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