Abstract
Given an N1-free abelian group G we characterize the class CG of all torsion abelian groups T satisfying Ext (G, T) = 0 assuming the special continuum hypothesis CH. Moreover, in Gödel’s constructible universe we prove that this characterizes CG for arbitrary torsion-free abelian G. It follows that there exists some ugly N1-free abelian groups.
Original language | English |
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Pages (from-to) | 1617-1626 |
Number of pages | 10 |
Journal | Rocky Mountain Journal of Mathematics |
Volume | 32 |
Issue number | 4 |
DOIs | |
State | Published - 2002 |