Surface groups are flexibly stable
Nir Lazarovich
Technion–Israel Institute of Technology, Haifa, IsraelArie Levit
Tel Aviv University, IsraelYair Minsky
Yale University, New Haven, USA
Abstract
We show that surface groups are flexibly stable in permutations. This is the first non-trivial example of a non-amenable flexibly stable group. Our method is purely geometric and relies on an analysis of branched covers of hyperbolic surfaces. Along the way we establish a quantitative variant of the LERF property for surface groups which may be of independent interest.
Cite this article
Nir Lazarovich, Arie Levit, Yair Minsky, Surface groups are flexibly stable. J. Eur. Math. Soc. (2024), published online first
DOI 10.4171/JEMS/1406