PreprintCC0arXiv
Small Kazhdan constants for small generating sets of linear groups
Abstract
Let G be a linear group with Kazhdan property (T) generated by d elements. We show that there are generating sets of size d+2 with arbitrarily small Kazhdan constants. We also prove the same conclusion for every finitely generated group admitting a non-elementary convergence action on a compact metrizable space. This includes non-elementary word-hyperbolic and relatively hyperbolic groups, as well as finitely generated non-elementary subgroups of word-hyperbolic groups.
Related
BibTeX
@misc{gelander2026small,
title = {{Small Kazhdan constants for small generating sets of linear groups}},
author = {Tsachik Gelander and Alex Lubotzky and Jvbin Yao},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.36098},
eprint = {2609.36098},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.36098},
note = {CC0},
}
RIS
TY - UNPB
TI - Small Kazhdan constants for small generating sets of linear groups
AU - Tsachik Gelander
AU - Alex Lubotzky
AU - Jvbin Yao
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2609.36098
UR - https://arxiv.org/abs/2609.36098
AB - Let G be a linear group with Kazhdan property (T) generated by d elements. We show that there are generating sets of size d+2 with arbitrarily small Kazhdan constants. We also prove the same conclusion for every finitely generated group admitting a non-elementary convergence action on a compact metrizable space. This includes non-elementary word-hyperbolic and relatively hyperbolic groups, as well as finitely generated non-elementary subgroups of word-hyperbolic groups.
ER -