Type: Article
Publication Date: 1970-01-01
Citations: 4
DOI: https://doi.org/10.1090/s0002-9939-1970-0260876-9
There exist continuously many finitely generated torsion-free groups which cannot be obtained from the infinite cyclic group by repeatedly forming the free product with an amalgamated subgroup of any two groups already obtained, taking subgroups, and forming ascending unions.