Mapping tori of free group automorphisms are coherent

Abstract

The mapping torus of an endomorphism $\Phi$ of a group $G$ is the HNN-extension $G_{*G}$ with bonding maps the identity and $\Phi$. We show that a mapping torus of an injective free group endomorphism has the property that its finitely generated subgroups are finitely presented and, moreover, these subgroups are of finite type.

DOI

https://doi.org/10.2307/121081

Authors

Mark Feighn

Michael Handel