The Hurwitz Matrix Equations and Multifour Groups.
The idempotent lifting theorem for almost completely decomposable abelian groups
The isomorphism relation on countable torsion free abelian groups
The isomorphism relation on countable torsion free abelian groups is non-Borel.
The nil-degree of a torsion-free Abelian group
The nilpotency of torsion-free rings with given type set
The nonseparability of simply presented mixed groups
It is demonstrated that an isotype subgroup of a simply presented abelian group can be simply presented without being a separable subgroup. In particular, the conjecture based on a variety of special cases that Warfield groups are absolutely separable is disproved.
The possibility of extending factorization results to infinite Abelian groups.
The pseudorational rank of an Abelian group.
The size of an annihilator in a factorization.
The splitting length of mixed Abelian groups of rank one
The splitting of the tensor product of two mixed abelian groups of rank one
The structure of digraphs associated with the congruence
We assign to each pair of positive integers and a digraph whose set of vertices is and for which there is a directed edge from to if . We investigate the structure of . In particular, upper bounds are given for the longest cycle in . We find subdigraphs of , called fundamental constituents of , for which all trees attached to cycle vertices are isomorphic.
The Structure of Ext (A,..) and V = L.
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.
The -inductive topology on abelian -groups
Theorien abelscher Gruppen mit einem einstelligen Prädikat
Torsion groups in cortorsion classes
Torsion-free abelian groups and completely decomposable -adic modules
Translačné štruktúry. Centrálne a necentrálne translačné štruktúry
Treillis d'idéaux et structure d'anneaux