-изоморфизмы смешанных абелевых групп ранга
Separable and vector groups whose projectively invariant subgroups are fully invariant.
Skeletons, bodies and generalized -algebras
Slender modules, endo-slender abelian groups and large cardinals
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...
Some morphisms of modules over the ring of pseudorational numbers.
Strong -groups
Subgroups of the Baer–Specker group with few endomorphisms but large dual
Assuming the continuum hypothesis, we construct a pure subgroup G of the Baer-Specker group with the following properties. Every endomorphism of G differs from a scalar multiplication by an endomorphism of finite rank. Yet G has uncountably many homomorphisms to ℤ.
Sur la limite du degré des groupes primitifs qui contiennent une substitution donnée.
The group of homomorphisms of Abelian torsion groups.
The homological dimension of a torsion-free abelian group of finite rank as a module over its ring of endomorphisms
The pseudorational rank of an Abelian group.
The theory of dual groups
We study the -theory of sequences of dual groups and give a complete classification of the -elementary classes by finding simple invariants for them. We show that nonstandard models exist.
Uniqueness theorems for global mixed groups.
Uniserial groups.
Unital Rings whose Additive Endomorphisms Commute.
Very Decomposable Abelian Groups.
When the intrinsic algebraic entropy is not really intrinsic
The intrinsic algebraic entropy ent(ɸ) of an endomorphism ɸ of an Abelian group G can be computed using fully inert subgroups of ɸ-invariant sections of G, instead of the whole family of ɸ-inert subgroups. For a class of groups containing the groups of finite rank, aswell as those groupswhich are trajectories of finitely generated subgroups, it is proved that only fully inert subgroups of the group itself are needed to comput ent(ɸ). Examples show how the situation may be quite different outside...
Абелевы группы без кручения конечного ранга без нильпотентных эндоморфизмов