English

Growing Spines Ad Infinitum

Logic 2025-04-08 v3 Group Theory

Abstract

We show that every non-trivial ordered abelian group GG is augmentable by infinite elements, i.e., we have GHGG\preccurlyeq H\oplus G for some non-trivial ordered abelian group HH. As an application, we show that when kk is a field of characteristic 0, then kk is not tt-henselian if and only if all henselian valuations with residue field kk are (\emptyset-)definable.

Keywords

Cite

@article{arxiv.2501.10531,
  title  = {Growing Spines Ad Infinitum},
  author = {Blaise Boissonneau and Anna De Mase and Franziska Jahnke and Pierre Touchard},
  journal= {arXiv preprint arXiv:2501.10531},
  year   = {2025}
}

Comments

19 pages. The paper has been amended to recognize priority of a former result

R2 v1 2026-06-28T21:09:50.873Z