Bounded Generation for $SL_n(Λ)$
Nir Avni, Chen Meiri
TL;DR
This work proves unconditional bounded generation for $SL_d(\Lambda)$ with $d\ge 3$ when $\Lambda$ is an $S$-order in a central division algebra over a number field and $SL_3(\Lambda)$ is generated by elementary matrices. The authors reduce to the case $d=3$, and develop a framework based on $S$-congruence and commgruence completions, ultrafilter ultrapowers, and discrete metaplectic extensions. By translating a potential failure of bounded generation into the existence of a nontrivial metaplectic extension and then ruling out such extensions via metaplectic kernel arguments, they force the desired bounded generation by elementary matrices. The approach blends local–global methods, Bass–Masser–Draxl–Mor-type stability results, and central extension theory to achieve a new isotropic higher-rank bounded generation result with potential implications for width questions in arithmetic groups.
Abstract
Let $Λ$ be an order in a division algebra over a number field. We prove, under some conditions, that $SL_3(Λ)$ is boundedly generated by elementary matrices.
