3 papers
math.GR2025
On the isomorphism problem for generalized Baumslag-Solitar groups: angles
Dario Ascari, Montserrat Casals-Ruiz, Ilya Kazachkov
We introduce a new isomorphism invariant for generalized Baumslag-Solitar (GBS) groups, which we call the limit angle. Unlike previously known invariants, which are primarily algeb…
math.GR2025
On the isomorphism problem for generalized Baumslag-Solitar groups: invariants and flexible configurations
Dario Ascari, Montserrat Casals-Ruiz, Ilya Kazachkov
We prove that the isomorphism problem is decidable for generalized Baumslag-Solitar (GBS) groups with one quasi-conjugacy class and full support gaps. In order to do so we introduc…
math.GR2025
On the isomorphism problem for cyclic JSJ decompositions: vertex elimination
Dario Ascari, Montserrat Casals-Ruiz, Ilya Kazachkov
We introduce two new moves on graphs of groups with cyclic edge groups that preserve the fundamental group. These moves allow us to address the isomorphism problem without the use…