Semi-Generalized co-Bassian Groups

As a common non-trivial generalization of the notion of a generalized co-Bassian group, recently defined by the third author, we introduce the notion of a semi-generalized co-Bassian group and initiate its comprehensive study. Specifically, we give a complete characterization of these groups in the cases of p-torsion groups and groups of finite torsion-free rank by showing that these groups can be completely determined in terms of generalized finite p-ranks and also depends on their quotients modulo the maximal torsion subgroup. Surprisingly, for p-primary groups, the concept of a semi-generalized co-Bassian group is closely related to that of a generalized co-Bassian group.