The topology at infinity of an arithmetic group

Andrew Putman (University of Notre Dame)

Monday 17th May, 2021 16:00-17:00 Online


Let G be an arithmetic group like SL(n,Z). Borel and Serre proved a beautiful theorem showing that the topology of G “at infinity” can be modeled by an appropriate Tits building. I will discuss a circle of ideas combining insights from topology, number theory, and representation theory to use this to shed light on G and its subgroups.

The talk will be preceded by a tea time at 3:45pm. The Zoom link for the seminar is and the passcode is the genus of the two-dimensional sphere (4 letters, all lowercase).

If you would like to subscribe to the seminar mailing list, go to, search "Geometry & Topology" and click "Join group".

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