Resumen de The structure of compact coGalois groups

Edgar E. Enochs , Sergio Estrada Domínguez

• The coGalois groups of torsion free covers were defined in E. Enochs, J.R. García Rozas, O.M.G. Jenda and L. Oyonarte: Compact coGalois groups. Math. Proc. Cambridge Phil. Soc. (2) 128 (2000), 233-244, and were shown to have a natural topology. In that paper there was also given a necessary and sufficient condition on an abelian group in order that the coGalois group of its torsion free cover be compact. However the question of the structure of these compact groups was left open. In this paper we give a complete description of these compact groups. We also give a complete description of the coGalois groups associated with the torsion free cover of divisible groups.