Event

Anush Tserunyan (McGill) - Quasi-treeable equivalence relations are treeable

Ort: SG 3-12

A result from geometric group theory says that if a Cayley graph of a finitely generated group is tree-like (more precisely, is quasi-isometric to a tree) then the group is virtually free. We prove the analogue of this in the context of countable Borel equivalence relations, thus answering a question of R. Tucker-Drob from 2015. Our method exploits the Stone duality between certain families of cuts in a graph and median graphs (1-skeleta of CAT(0) cube complexes). This is joint work with R. Chen, A. Poulin, and R. Tao. One of our results was also independently proved by Héctor Jardón-Sánchez via a different method.
 
Seminar Website: https://www.math.uni-leipzig.de/cms2/en/institut/seminare/acseminar/">https://www.math.uni-leipzig.de/cms2/en/institut/seminare/acseminar/

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Beginn: April 4, 2024, 1:15 p.m.

Ende: April 4, 2024, 2:15 p.m.