Abstract
We show that surface groups are flexibly stable in permutations. This is the first nontrivial 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.
Original language | English |
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Pages (from-to) | 1739-1768 |
Number of pages | 30 |
Journal | Journal of the European Mathematical Society |
Volume | 27 |
Issue number | 4 |
DOIs | |
State | Published - 2025 |
Keywords
- CAT.‒1/
- LERF
- Stability in permutations
- combinatorial group theory
- flexible stability
- surface groups
All Science Journal Classification (ASJC) codes
- General Mathematics
- Applied Mathematics