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Mathematics Colloquium

Tuesday, May 7, 2019
4:00pm to 5:00pm
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Linde Hall 310
The Johnson filtration is finitely generated
Andrew Putnam, Department of Mathematics, University of Notre Dame,

The Johnson filtration is an important and mysterious sequence of subgroups of the mapping class group. I will prove that each term is finitely generated once the genus is sufficiently large. The main tool is the Bieri-Neumann-Strebel invariant. No prior knowledge of the mapping class group or the BNS invariant will be assumed. This is joint work with Tom Church and Mikhail Ershov.

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