EuDML | Browse

We prove that if $G$ is an Abelian $p$ -group of length not exceeding $ω$ and $H$ is its $p^{ω + n}$ -projective subgroup for $n \in ℕ \cup {0}$ such that $G / H$ is countable, then $G$ is also $p^{ω + n}$ -projective. This enlarges results of ours in (Arch. Math. (Brno), 2005, 2006 and 2007) as well as a classical result due to Wallace (J. Algebra, 1971).

On Fuchs' problem 76.

Birge Zimmermann-Huisgen (1979)

Journal für die reine und angewandte Mathematik

On localizations of torsion abelian groups

José L. Rodríguez, Jérôme Scherer, Lutz Strüngmann (2004)

Fundamenta Mathematicae

As is well known, torsion abelian groups are not preserved by localization functors. However, Libman proved that the cardinality of LT is bounded by ${| T |}^{ℵ ₀}$ whenever T is torsion abelian and L is a localization functor. In this paper we study localizations of torsion abelian groups and investigate new examples. In particular we prove that the structure of LT is determined by the structure of the localization of the primary components of T in many cases. Furthermore, we completely characterize the relationship...

On neat-injective groups

Ramana Murthy, N.V., Mashhood, Asif (1991)

Portugaliae mathematica

On projective and injective objects of the categories dual to $𝔄𝔅$ .

Zvyagina, M.B. (2005)

Zapiski Nauchnykh Seminarov POMI

On some subgroups of infinite rank Butler groups

Manfred Dugas (1988)

Rendiconti del Seminario Matematico della Università di Padova

On subfunctors of the identity

Radoslav Dimitrić (1986)

Rendiconti del Seminario Matematico della Università di Padova

Pure extensions of locally compact abelian groups

Peter Loth (2006)

Rendiconti del Seminario Matematico della Università di Padova

Quasi-balanced torsion-free groups

H. Pat Goeters, William Ullery (1998)

Commentationes Mathematicae Universitatis Carolinae

An exact sequence $0 \to A \to B \to C \to 0$ of torsion-free abelian groups is quasi-balanced if the induced sequence $0 \to 𝐐 \otimes Hom (X, A) \to 𝐐 \otimes Hom (X, B) \to 𝐐 \otimes Hom (X, C) \to 0$ is exact for all rank-1 torsion-free abelian groups $X$ . This paper sets forth the basic theory of quasi-balanced sequences, with particular attention given to the case in which $C$ is a Butler group. The special case where $B$ is almost completely decomposable gives rise to a descending chain of classes of Butler groups. This chain is a generalization of the chain of Kravchenko classes that arise from balanced...

Quasiprojective and quasi-injective finite valuated groups

C. Vinsonhaler, W. Wickless (1981)

Colloquium Mathematicae

Self- $c$ -injective abelian groups

Simion Breaz, Grigore Călugăreanu (2006)

Rendiconti del Seminario Matematico della Università di Padova

Currently displaying 21 – 40 of 70

Previous Page 2 Next