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On the Lattice of Cotorsion Theories

✍ Scribed by Rüdiger Göbel; Saharon Shelah; Simone L Wallutis

Publisher
Elsevier Science
Year
2001
Tongue
English
Weight
181 KB
Volume
238
Category
Article
ISSN
0021-8693

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✦ Synopsis

We discuss the lattice of cotorsion theories for abelian groups. First we show that the sublattice of the well-studied rational cotorsion theories can be identified with the well-known lattice of types. Using a recently developed method for making Ext vanish, we also prove that any power set together with the ordinary set Ž . inclusion and thus any poset can be embedded into the lattice of all cotorsion theories.

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