Quasi-Endomorphism Rings of Some Quasi-Decomposable Torsion-Free Abelian Groups of Rank 4

Abstract

We obtain a description of quasi-endomorphism rings of torsion-free Abelian groups G of rank 4, quasi-decomposable into a direct sum of groups A1 and A2 of rank 1 and a strongly indecomposable group B of rank 2 in the case where the quasi-homomorphism group ℚ ⨂ Hom(A2,B) has rank 2.