Document Type

Peer-Reviewed Article

Publication Date

11-2016

Abstract

Ulm’s Theorem presents invariants that classify countable abelian torsion groups up to isomorphism. Barwise and Eklof extended this result to the classification of arbitrary abelian torsion groups up to L∞ω-equivalence. In this paper, we extend this classification to a class of mixed Zp-modules which includes all Warfield modules and is closed under L∞ω-equivalence. The defining property of these modules is the existence of what we call a partial decomposition basis, a generalization of the concept of decomposition basis. We prove a complete classification theorem in L∞ω using invariants deduced from the classical Ulm and Warfield invariants.

Comments

Version posted in an arxiv.org preprint https://arxiv.org/pdf/1507.06572.pdf

DOI

10.1007/s00153-016-0506-7

Included in

Mathematics Commons

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