Abstract:It is shown, under ZFC, that a \text {$B_2$-group} has the interesting property of being $\aleph _0$-prebalanced in every torsion-free abelian group in which it is a pure subgroup. As a consequence, we obtain alternate proofs of some well-known theorems on \text {$B_2$-group}s.
Keywords: torsion-free abelian groups, Butler groups, \text {$B_2$-group}s, $\aleph _0$-prebalanced subgroups, completely decomposable groups, separative subgroups
AMS Subject Classification: Primary 20K20