English

Retracts of vertex sets of trees and the almost stability theorem

Group Theory 2011-11-09 v3

Abstract

Let G be a group, let T be an (oriented) G-tree with finite edge stabilizers, and let VT denote the vertex set of T. We show that, for each G-retract V' of the G-set VT, there exists a G-tree whose edge stabilizers are finite and whose vertex set is V'. This fact leads to various new consequences of the almost stability theorem. We also give an example of a group G, a G-tree T and a G-retract V' of VT such that no G-tree has vertex set V'.

Keywords

Cite

@article{arxiv.math/0510151,
  title  = {Retracts of vertex sets of trees and the almost stability theorem},
  author = {Warren Dicks and M. J. Dunwoody},
  journal= {arXiv preprint arXiv:math/0510151},
  year   = {2011}
}

Comments

15 pages, 0 figures. Formerly titled "Some refinements of the almost stability theorem". Version 3