2026/07/21 by Dario Ascari, Alessandra Caraceni
#math.GR
The isomorphism problem for generalized Baumslag-Solitar (GBS) groups is a long-standing open problem. We prove that, in the random model considered here, a GBS graph with many edges is flexible with high probability. Since the isomorphism problem is decidable for flexible GBS graphs, this gives a high-probability decidability result for random GBS groups in this regime.