English

Logarithmic bounds for the diameters of some Cayley graphs

Group Theory 2021-10-05 v3 Number Theory

Abstract

Let SGLn(Z)S\subset\text{GL}_n(\mathbb Z) be a finite symmetric set. We show that if the Zariski closure of Γ=S\Gamma=\langle S\rangle is a product of SLd\text{SL}_d or a special affine linear group, then the diameter of the Cayley graph Cay(Γ/Γ(q),πq(S))\text{Cay}(\Gamma/\Gamma(q),\pi_q(S)) is O(logq)O(\log q), where qq is an arbitrary positive integer, πq:ΓΓ/Γ(q)\pi_q:\Gamma\to \Gamma/\Gamma(q) is the canonical projection induced by the reduction modulo qq, and the implied constant depends only on SS.

Keywords

Cite

@article{arxiv.1910.05718,
  title  = {Logarithmic bounds for the diameters of some Cayley graphs},
  author = {Lam Pham and Xin Zhang},
  journal= {arXiv preprint arXiv:1910.05718},
  year   = {2021}
}

Comments

13 pages, part of the paper rewritten, to appear at Journal of Group Theory