Alan Logan

Fixed subgroups of automorphisms of Generalised Baumslag-Solitar groups

Fixed subgroups of automorphisms of finitely generated free groups have been studied since the 1970s, and are known to be well-behaved. For example, they are finitely generated, of rank bounded above by the ambient free group.

This talk considers the analogous questions - finite generation and bounded generation of fixed subgroups - in the case of Generalised Baumslag-Solitar (GBS) groups. The main technical aspects of the talk will cover group actions on trees, which is how GBS groups are defined. Joint work with Oli Jones.