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Department of Mathematics,
University of California San Diego

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Math 211B - Group Actions Seminar

Amanda Wilkens

University of Texas, Austin

Poisson-Voronoi tessellations and fixed price in higher rank

Abstract:

We overview the cost of a group action, which measures how much information is needed to generate its induced orbit equivalence relation, and the ideal Poisson-Voronoi tessellation (IPVT), a new random limit with interesting geometric features. In recent work, we use the IPVT to prove all measure preserving and free actions of a higher rank semisimple Lie group on a standard probability space have cost 1, answering Gaboriau's fixed price question for this class of groups. We sketch a proof, which relies on some simple dynamics of the group action and the definition of a Poisson point process. No prior knowledge on cost, IPVTs, or Lie groups will be assumed. This is joint work with Mikolaj Fraczyk and Sam Mellick.

Brandon Seward

October 3, 2023

10:00 AM

APM 7218 and Zoom ID 967 4109 3409
 

Research Areas

Ergodic Theory and Dynamical Systems

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