English

Explicit Generators for the Stabilizers of Rational Points in Thompson's Group $F$

Group Theory 2024-11-21 v2

Abstract

We construct explicit finite generating sets for the stabilizers in Thompson's group FF of rational points of a unit interval or a Cantor set. Our technique is based on the Reidemeister-Schreier procedure in the context of Schreier graphs of such stabilizers in FF. It is well known that the stabilizers of dyadic rational points are isomorphic to F×FF\times F and can thus be generated by 4 explicit elements. We show that the stabilizer of every non-dyadic rational point b(0,1)b\in (0,1) is generated by 5 elements that are explicitly calculated as words in generators x0,x1x_0, x_1 of FF that depend on the binary expansion of bb. We also provide an alternative simple proof that the stabilizers of all rational points are finitely presented.

Keywords

Cite

@article{arxiv.2401.00404,
  title  = {Explicit Generators for the Stabilizers of Rational Points in Thompson's Group $F$},
  author = {Krystofer Baker and Dmytro Savchuk},
  journal= {arXiv preprint arXiv:2401.00404},
  year   = {2024}
}

Comments

19 pages, 9 figures and pictures