Non-existence of universal members in classes of abelian groups

Saharon Shelah

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arXiv · math/9808139

Non-existence of universal members in classes of abelian groups

Saharon Shelah

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Abstract

We prove that if mu^+< lambda =cf(lambda)< mu^{aleph_0}, then there is no universal reduced torsion free abelian group. Similarly if aleph_0< lambda < 2^{aleph_0}. We also prove that if 2^{aleph_0}< mu^+< lambda =cf(lambda)< mu^{aleph_0}, then there is no universal reduced separable abelian p-group in lambda. (Note: both results fail if lambda = lambda^{aleph_0} or if lambda is strong limit, cf (mu)= aleph_0< mu).

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BibTeX RIS

Saharon Shelah. 1998-08-15. Non-existence of universal members in classes of abelian groups. https://arxiv.org/abs/math/9808139

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