Graphs of groups with isomorphic fundamental group (Q1109892)

The notion of graphs of groups was defined by Serre and Bass in 1977. They also defined the fundamental group of a graph of groups with respect to a base vertex. The author in this interesting paper treats the problem: Whether graphs of groups can be used for a classification of groups themselves. He obtains a nice theorem in this direction, and giving the proof of a result which says that under certain convenient conditions two graphs of groups have isomorphic subgroups. In the proof some methods of combinatorial group theory are used.