Self-pseudoprojective completely decomposable Abelian groups.
Self-small products of abelian groups
Let and be two abelian groups. The group is called -small if the covariant functor commutes with all direct sums and is self-small provided it is -small. The paper characterizes self-small products applying developed closure properties of the classes of relatively small groups. As a consequence, self-small products of finitely generated abelian groups are described.
Separable and vector groups whose projectively invariant subgroups are fully invariant.
Singular homology groups of one-dimensional Peano continua
Let X be a one-dimensional Peano continuum. Then the singular homology group H₁(X) is isomorphic to a free abelian group of finite rank or the singular homology group of the Hawaiian earring.
Skeletons, bodies and generalized -algebras
Small almost free modules with prescribed topological endomorphism rings
Some generalizations of torsion-free Crawley groups
In this paper we investigate two new classes of torsion-free Abelian groups which arise in a natural way from the notion of a torsion-free Crawley group. A group is said to be an Erdős group if for any pair of isomorphic pure subgroups with , there is an automorphism of mapping onto ; it is said to be a weak Crawley group if for any pair of isomorphic dense maximal pure subgroups, there is an automorphism mapping onto . We show that these classes are extensive and pay attention to...
Subsemigroups of the finite complexes of a group.
Sur les groupes quasi-purs-projectifs sans torsion