Subgroup separability, knot groups and graph manifolds
Subgroup separability, knot groups and graph manifolds
This paper answers a question of Burns, Karrass and Solitar by giving examples of knot and link groups which are not subgroup-separable. For instance, it is shown that the fundamental group of the square knot complement is not subgroup separable. Let $L$ denote the fundamental group of the link consisting …