The $\Sigma$-invariants of Thompson's group $F$ via Morse theory

Stefan Witzel, Matthew C. B. Zaremsky

Bieri, Geoghegan and Kochloukova computed the BNSR-invariants ${\Sigma }^m(F)$ of Thompson's group $F$ for all $m$. We recompute these using entirely geometric techniques, making use of th…