A short account of why Thompson's group $F$ is of type $\textrm{F}_\infty$

TL;DR

This paper presents a streamlined, modern proof that Thompson's group F is of type F_infinity, simplifying previous complex proofs and focusing solely on this property.

Contribution

It provides a clear, accessible exposition of the modern proof that Thompson's group F is of type F_infinity, avoiding complex generalizations.

Findings

Thompson's group F is of type F_infinity.

The modern proof is more streamlined and generalizable.

The paper isolates the proof specifically for F, without additional properties.

Abstract

In 1984 Brown and Geoghegan proved that Thompson's group $F$ is of type $\textrm{F}_\infty$, making it the first example of an infinite dimensional torsion-free group of type $\textrm{F}_\infty$. Over the decades a different, shorter proof has emerged, which is more streamlined and generalizable to other groups. It is difficult, however, to isolate this proof in the literature just for $F$ itself, with no complicated generalizations considered and no additional properties proved. The goal of this expository note then is to present the "modern" proof that $F$ is of type $\textrm{F}_\infty$, and nothing else.