Paul Hill, Charles Megibben
The nonseparability of simply presented mixed groups

Comment.Math.Univ.Carolinae 39,1 (1998) 1-5.

Abstract:It is demonstrated that an isotype subgroup of a simply presented abelian group can be simply presented without being a separable subgroup. In particular, the conjecture based on a variety of special cases that Warfield groups are absolutely separable is disproved.

Keywords: Warfield groups, simply presented, isotype subgroup, separable subgroup
AMS Subject Classification: Primary 20K21, 20K27; Secondary 20F05