Automatic continuity of ℵ1-free groups
نویسندگان
چکیده
منابع مشابه
Some ugly א1-free abelian groups
Given an א1-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 constructable universe we prove that this characterizes CG for arbitrary torsion-free abelian G. It follows that there exist some ugly א1-free abelian groups.
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Given an א1-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 constructable universe we prove that this characterizes CG for arbitrary torsion-free abelian G. It follows that there exist some ugly א1-free abelian groups.
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ژورنال
عنوان ژورنال: Israel Journal of Mathematics
سال: 2020
ISSN: 0021-2172,1565-8511
DOI: 10.1007/s11856-020-2006-z