Forest Diagrams and Lengths for the Generalised Thompson's Group $F(n)$
Group Theory
2026-05-11 v1
Abstract
We extend the concept of two-way forest diagrams, introduced by Belk and Brown in 2003, to represent elements of as a pair of infinite, bounded -ary forests together with an order-preserving bijection of the leaves. This representation allows us to develop an alternative way to compute the length of an element of , distinct from the formula established by Fordham and Cleary in 2009. As an application of our length formula, we re-prove the existence of dead end elements in and show that their depth is always two, first proved by Wladis in 2009.
Cite
@article{arxiv.2605.06739,
title = {Forest Diagrams and Lengths for the Generalised Thompson's Group $F(n)$},
author = {Martín Gómez Reynolds},
journal= {arXiv preprint arXiv:2605.06739},
year = {2026}
}
Comments
20 pages, 23 figures