The structure of Ext(A,Z) and GCH: possible co-Moore spaces

Paul C. Eklof, Saharon Shelah

We consider what Ext(A,Z) can be when A is torsion-free and Hom(A,Z)=0. We thereby give an answer to a question of Golasinski and Goncalves which asks for the divisible Abelian gro…