Аннотация:
It is well-known by Hill-Griffith that there exist $\aleph_1$-separable $p$-primary groups which are not direct sums of cycles. A problem of challenging interest, mainly due to Hill (Rocky Mount. J. Math., 1971), is under what extra circumstances on the group structure this holds untrue, that is every $\aleph_1$-separable $p$-group is a direct sum of cyclic groups. We prove here that any weakly $\aleph_1$-separable $p$-group of cardinality not exceeding $\aleph_1$ is quasi-complete precisely when it is a bounded direct sum of cycles, thus partly answering the posed question in the affirmative.