English

Hall's Theorem for limit groups

Group Theory 2007-06-07 v4 Geometric Topology

Abstract

A celebrated theorem of Marshall Hall Jr. implies that finitely generated free groups are subgroup separable and that all of their finitely generated subgroups are retracts of finite-index subgroups. We use topological techniques inspired by the work of Stallings to prove that all limit groups share these two properties. This answers a question of Sela.

Keywords

Cite

@article{arxiv.math/0605546,
  title  = {Hall's Theorem for limit groups},
  author = {Henry Wilton},
  journal= {arXiv preprint arXiv:math/0605546},
  year   = {2007}
}

Comments

39 pages, 4 figures, added a double-coset-separability result, to appear in GAFA