Volume 28 • Number 2 • 2006     • The Cyclic Subgroup Separability of Certain HNN Extensions P.C. Wong and K.B. Wong Abstract. In this note we give characterisations for certain HNN extensions with central associated subgroups to be cyclic subgroup separable. We then apply our results to HNN extensions of polycyclic-by-finite groups and Fuchsian groups. 2000 Mathematics Subject Classification: 20E06, 20E26. Full text: PDF