The Sigma invariants for the Golden Mean Thompson group
Group Theory
2025-06-10 v2
Abstract
We use a method of Bieri, Geoghegan and Kochloukova to calculate the BNSR-invariants for the irrational slope Thompson's group . To do so we establish conditions under which the Sigma invariants coincide with those of a subgroup of finite index, addressing a problem posed by Strebel.
Cite
@article{arxiv.2309.12213,
title = {The Sigma invariants for the Golden Mean Thompson group},
author = {Lewis Molyneux and Brita Nucinkis and Yuri Santos Rego},
journal= {arXiv preprint arXiv:2309.12213},
year = {2025}
}
Comments
19 pages. v2: Major revision after referee's comments, corrected inacurracies/inconsistencies throughout the text, improved proof of the main theorem, restated results on Sigma invariants and characters for clarity, expanded on related work. Final version, to appear in the New York Journal of Mathematics