A non-Hopfian relatively hyperbolic group with respect to a Hopfian subgroup
arXiv:2304.10012
Abstract
We produce an example demonstrating that every finitely generated relatively hyperbolic group with respect to a collection of Hopfian subgroups need not be Hopfian. This answers a question of Osin \cite[Problem 5.5]{Osin} in the negative.
15 pages