Thread: Retraction math help View Single Post
 P: 867 The HNN-theorem says that every countable group can be embedded into a group with two generators. Could this be helpful? In other words would the group $$\bigoplus_{i\in\mathbb{N}}\mathbb{Z}_{p_i}$$ be a countable group with countably many retracts? (In light of the previous question this may be the right way to go)