English

The congruence topology, Grothendieck duality and thin groups

Group Theory 2017-09-20 v1

Abstract

This paper answers a question raised by Grothendieck in 1970 on the "Grothendieck closure" of an integral linear group and proves a conjecture of the first author made in 1980. This is done by a detailed study of the congruence topology of arithmetic groups, obtaining along the way, an arithmetic analogue of a classical result of Chevalley for complex algebraic groups. As an application we also deduce a group theoretic characterization of thin subgroups of arithmetic groups.

Keywords

Cite

@article{arxiv.1709.06179,
  title  = {The congruence topology, Grothendieck duality and thin groups},
  author = {Alexander Lubotzky and T. N. Venkataramana},
  journal= {arXiv preprint arXiv:1709.06179},
  year   = {2017}
}

Comments

24 pages