Unicorn paths and hyperfiniteness for the mapping class group

Piotr Przytycki; Marcin Sabok

doi:10.1017/fms.2021.34

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arXiv · 2006.08872

Unicorn paths and hyperfiniteness for the mapping class group

Piotr Przytycki·Marcin Sabok

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Abstract

Let S be an orientable surface of finite type. Using Pho-On's infinite unicorn paths, we prove the hyperfiniteness of orbit equivalence relations induced by the actions of the mapping class group of S on the Gromov boundaries of the arc graph and the curve graph of S. In the curve graph case, this strengthens the results of Hamenstädt and Kida that this action is universally amenable and that the mapping class group of S is exact.

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BibTeX RIS

Piotr Przytycki, Marcin Sabok. 2021-04-09. Unicorn paths and hyperfiniteness for the mapping class group. https://doi.org/10.1017/fms.2021.34

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