Cohomology of arithmetic groups and characteristic classes of manifold bundles

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Speaker: 
Bena Tshishiku
Institution: 
Harvard University
Time: 
Mon, 01/08/2018 - 4:00pm - 5:00pm
Host: 
Jesse Wolfson
Location: 
RH 340P

A basic problem in the study of fiber bundles is to compute the ring H*(BDiff(M)) of characteristic classes of bundles with fiber a smooth manifold M. When M is a surface, this problem has ties to algebraic topology, geometric group theory, and algebraic geometry. Currently, we know only a very small percentage of the total cohomology. In this talk I will explain some of what is known and discuss some new characteristic classes (in the case dim M >>0) that come from the unstable cohomology of arithmetic groups.