Abstract
It is a well-known homological fact that every Abelian group G has the property that Hom (G, -) commutes with direct products. Here we investigate the 'dual' property: an Abelian group G is said to be cosmall if Hom (-, G) commutes with direct products. We show that cosmall groups are cotorsion-free and that no group of cardinality less than a strongly compact cardinal can be cosmall. In particular, if there is a proper class of strongly compact cardinals, then there are no cosmall groups.
Original language | English |
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Pages (from-to) | 510-518 |
Number of pages | 9 |
Journal | Journal of Algebra |
Volume | 317 |
Issue number | 2 |
DOIs | |
Publication status | Published - 15 Nov 2007 |
Externally published | Yes |
Keywords
- Abelian groups
- Homological algebra
- Set theory