On Determinability of a Quotient Divisible Abelian Group of Rank 1 by Its Automorphism Group

A criterion for determinability of a quotient divisible Abelian group of rank 1 by its automorphism group in the class of quotient divisible Abelian groups of rank 1 is considered in the paper

The hyperstability of AQ-Jensen functional equation on 2-divisible abelian group and inner product spaces

In this paper, we prove the hyperstability of the following mixed additive-quadratic-Jensen functional equation $$2f({{x + y} \over 2}) + f({{x - y} \over 2}) + f({{y - x} \over 2}) = f(x) + f(y)$$ in the class of functions from an 2-divisible abelian group G into a Banach space.

Computation of the norm factor group over Henselian fields and tame Brauer group of generalized local fields

Let F be a Henselian field. For a finite extension K of F, the norm factor group [Formula: see text] is computed. As an application, structure of the tame Brauer group of a generalized local field is determined. In particular, we observe that every torsion divisible abelian group is realizable as the tame Brauer group of a generalized local field.

A Locally Compact Non Divisible Abelian Group Whose Character Group Is Torsion Free and Divisible

It was claimed by Halmos in 1944 that if G is a Hausdorff locally compact topological abelian group and if the character group of G is torsion free, then G is divisible. We prove that such a claim is false by presenting a family of counterexamples. While other counterexamples are known, we also present a family of stronger counterexamples, showing that even if one assumes that the character group of G is both torsion free and divisible, it does not follow that G is divisible.

On Injective Sheaves

A divisible abelian group D can be characterized by the following property: Every homomorphism from an abelian group A to D can be extended to every abelian group B containing A. This together with the result that every abelian group can be embedded in a divisible group is a crucial point in many investigations on abelian groups. It was Baer, [1], who extended this result to modules over an arbitrary ring, replacing divisible groups by injective modules, that is, modules with the property mentioned above. Another proof was found later by Eckmann and Schopf, [3]. This proof assumes the proposition to hold for abelian groups and transfers it in a very simple and elegant manner to modules. In the sequel, we shall refer to this proof as to the Eckmann-Schopf proof.