Classi di gruppi abeliani chiuse rispetto alle immagini omomorfe ed ai limiti proiettivi
Gruppi monotóni di successioni intere
Polyserial modules over valuation domains
Abelian groups of zero adjoint entropy
The notion of adjoint entropy for endomorphisms of an Abelian group is somehow dual to that of algebraic entropy. The Abelian groups of zero adjoint entropy, i.e. ones whose endomorphisms all have zero adjoint entropy, are investigated. Torsion groups and cotorsion groups satisfying this condition are characterized. It is shown that many classes of torsionfree groups contain groups of either zero or infinite adjoint entropy. In particular, no characterization of torsionfree groups of zero adjoint...
Almost perfect domains
Commutative rings all of whose quotients over non-zero ideals are perfect rings are called almost perfect. Revisiting a paper by J. R. Smith on local domains with TTN, some basic results on these domains and their modules are obtained. Various examples of local almost perfect domains with different features are exhibited.
The hierarchy of uniserial modules over a valuation domain.
A characterization of countable Butler groups
Fully inert submodules of torsion-free modules over the ring of p-adic integers
Fully inert submodules of torsion-free -modules are investigated. It is proved that if the module considered is either free or complete, these submodules are exactly those which are commensurable with fully invariant submodules; examples are given of torsion-free -modules for which this property fails.
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