Solvable Groups of Exponential Growth and HNN Extensions
arXiv:math/9912040
Abstract
We prove the following version of Milnor's theorem on solvable groups of exponential growth: A finitely generated solvable group which is not polycyclic contains an ascending HNN extension. Consequently, a finitely generated solvable group is ERF iff it is polycyclic.
to appear in Groups Korea-98, De Gruyter