Cocycle stability in permutations of random simplicial complexes
Abstract
Finding a non-sofic hyperbolic group will resolve two major problems in geometric group theory: Are there non sofic groups? Are there non residually finite hyperbolic groups? In this paper, we propose a new probabilistic approach to this problem, based on the cocycle stability in permutations of random 2-dimensional Linial-Meshulam complexes. Specifically, we study their cocycle stability rate, which measures how far cochains with small coboundaries are from being cocycles. Our main contribution is the following: If, in a middle triangle density range, these random complexes typically have a linear cocycle stability rate, then there exists a non-sofic hyperbolic group. Our proof method is inspired by a well known fact about the non local testability of Sipser-Spielman expander codes.
Cite
@article{arxiv.2509.21566,
title = {Cocycle stability in permutations of random simplicial complexes},
author = {Michael Chapman and Yuval Peled},
journal= {arXiv preprint arXiv:2509.21566},
year = {2025}
}
Comments
Second version, 34 pages, 1 figure