The structure of Ext(A,Z) and GCH: possible co-Moore spaces
arXiv:math/0303344
Abstract
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 groups which can be the type of a co-Moore space.