English

Nielsen-Thurston orderings and the space of braid orderings

Group Theory 2009-06-16 v1

Abstract

We study the topological space of left-orderings of the braid group, and its subspace of Nielsen-Thurston orderings. Our main result is that no Nielsen-Thurston ordering is isolated in the space of braid orderings. In the course of the proof, we classify the convex subgroups and calculate the Conradian soul for any Nielsen-Thurston ordering of B_n. We also prove that for a large class of Nielsen-Thurston orderings, including all those of infinite type, a stronger result holds: they are approximated by their own conjugates. On the other hand, we suggest an example of a Nielsen-Thurston ordering which may not be approximated by its conjugates.

Keywords

Cite

@article{arxiv.0906.2605,
  title  = {Nielsen-Thurston orderings and the space of braid orderings},
  author = {Andres Navas and Bert Wiest},
  journal= {arXiv preprint arXiv:0906.2605},
  year   = {2009}
}