Arithmetic approach to the spectral gap problem

Abstract: 

The spectral gap is an analytic property of group actions which can be described as absence of "almost invariant vectors" or more quantitatively in terms of norm bounds for suitable averaging operators. In the setting of homogeneous spaces this property also has a profound number-theoretic meaning since it is closely related to understanding the automorphic representations. In this talk we survey some previous results about the spectral gap property and describe new approaches to deriving upper and lower bounds for the spectral gap.

This talk is part of the online Number Theory Web Seminar, and will be streamed live on Zoom.

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Organisers:

Mike Bennett (University of British Columbia)

Philipp Habegger (University of Basel)

Alina Ostafe (UNSW Sydney)