Butler Groups of Infinite Rank

Abstract

The class of pure subgroups of completely decomposable groups of finite rank was introduced and investigated by Butler in [5]. Lady called the groups in this class “Butler groups”. Some other authors studied Butler groups under different names (see Koehler [9] and the first author [3] and [4]). Recently, Arnold collected the known results on Butler groups in [1], and investigated more deeply this class of finite rank groups.