English

Commensurators of solvable S-arithmetic groups

Group Theory 2016-06-22 v1

Abstract

We show that the abstract commensurator of an S-arithmetic subgroup of a solvable algebraic group over Q is isomorphic to the Q-points of an algebraic group, and compare this with examples of nonlinear abstract commensurators of S-arithmetic groups in positive characteristic. In particular, we include a description of the abstract commensurator of the lamplighter group.

Cite

@article{arxiv.1309.0492,
  title  = {Commensurators of solvable S-arithmetic groups},
  author = {Daniel Studenmund},
  journal= {arXiv preprint arXiv:1309.0492},
  year   = {2016}
}

Comments

15 pages

R2 v1 2026-06-22T01:19:18.296Z