English

The decomposability problem for torsion-free abelian groups is analytic complete

Logic 2013-11-11 v1

Abstract

We discuss the decomposability of torsion-free abelian groups. We show that among computable groups of finite rank this property is Σ30\Sigma^0_3-complete. However, when we consider groups of infinite rank, it becomes Σ11\Sigma^1_1-complete, so it cannot be characterized by a first-order formula in the language of arithmetic.

Keywords

Cite

@article{arxiv.1311.1865,
  title  = {The decomposability problem for torsion-free abelian groups is analytic complete},
  author = {Kyle Riggs},
  journal= {arXiv preprint arXiv:1311.1865},
  year   = {2013}
}
R2 v1 2026-06-22T02:03:27.766Z