[For the entire collection see Zbl 0552.00004.]
Let \(\mu\) be a limit ordinal not cofinal with \(\omega\). A p-group H is called a \(\mu\)-elementary A-group if H is a subgroup of a totally projective group G of length \(\mu\) so that G/H is totally projective (not necessarily reduced), H is isotype in G and \(p^{\lambda}(G/H)=<p^{\lambda}G,H>/H\) when \(\lambda <\mu\). A p-group H is said to be an A-group if it is the direct sum of \(\mu\)-elementary A- groups for various limit ordinals \(\mu\) not cofinal with \(\omega\).
The author shows how to classify A-groups (but proofs are not included). Although A-groups are classified, there are some open questions and the author puts them: Problem 1. Are A-groups closed with respect to direct summands? Problem 2. Are there subclasses of A-groups other than S-groups (torsion subgroups of locally balanced-projectives) that serve as the torsion for interesting and natural classes of mixed groups? Besides the author introduces a class of A-modules and considers the same questions for it.