Class Group Actions: Measure Rigidity, L-functions and Sieving

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Ilya Khayutin, Northwestern University
Fine Hall 214

In-Person and Online Talk

Meeting ID:  920 2195 5230

Passcode:    The three-digit integer that is the cube of the sum of its digits. 

The linearization method of Dani-Margulis controls the amount of time a unipotent trajectory spends near invariant subvarieties of a homogeneous space. I will describe a problem in number theory where a similar control is desired for diagonalizable torus actions, but no analog of linearization holds. I will present two alternative approaches. The first one draws on measure rigidity for higher rank diagonalizable actions. The second approach is new joint work with V. Blomer and F. Brumley. This method uses the relation between torus periods on GL2 and L-functions. The two are ostensibly very different, but they share a
common underlying structure, and both rely crucially on sieve methods.