A Criterion for the Conjugacy Separability of Certain HNN Extensions of Groups,

We first prove the double coset separability of certain HNN extensions with cyclic associated subgroups. Using this we prove a criterion for the conjugacy separability of HNN extensions of conjugacy separable groups with cyclic associated subgroups. Applying this result we show that certain HNN extensions of free products of cycles and certain Baumslag–Solitar groups with cyclic associated subgroups are conjugacy separable.