Die Kollineationsgruppe verallgemeinerter André-Ebenen mit Homologien.
On reduced products of abelian groups
On some subgroups of infinite rank Butler groups
On a class of abelian p-groups.
The Functor Bext under the Negation of CH.
Die Struktur kartesischer Produkte ganzer Zahlen modulo kartesische Produkte ganzer Zahlen.
Every Cotorsion-free Algebra is an Endomorphism Algebra.
Automorphism Groups of Fields.
On Endomorphism Rings of Primary Abelian Groups.
Algebraisch kompakte Faktorgruppen.
AE-rings
Quotients of reflexive modules
A-Rings
A ring R is called an E-ring if every endomorphism of R⁺, the additive group of R, is multiplication on the left by an element of R. This is a well known notion in the theory of abelian groups. We want to change the "E" as in endomorphisms to an "A" as in automorphisms: We define a ring to be an A-ring if every automorphism of R⁺ is multiplication on the left by some element of R. We show that many torsion-free finite rank (tffr) A-rings are actually E-rings. While we have an example of a mixed...
An extension of Zassenhaus' theorem on endomorphism rings
Let R be a ring with identity such that R⁺, the additive group of R, is torsion-free. If there is some R-module M such that and , we call R a Zassenhaus ring. Hans Zassenhaus showed in 1967 that whenever R⁺ is free of finite rank, then R is a Zassenhaus ring. We will show that if R⁺ is free of countable rank and each element of R is algebraic over ℚ, then R is a Zassenhaus ring. We will give an example showing that this restriction on R is needed. Moreover, we will show that a ring due to A....
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