arXiv · 2512.04932
Growing Spines: Ad Infinitum et Ad Infinitesimalia
Abstract
We prove that for every ordered abelian group $G$ there exists a non-trivial ordered abelian group $H$ such that $G\preccurlyeq H\oplus G$ with the lexicographic order, and give a first-order characterization of ordered abelian group $G$ such that $G\preccurlyeq G\oplus H$ for some non-trivial $H$. We apply this to characterize which ordered abelian groups (respectively fields) ensure that any henselian valuation with said value group (respectively residue field) is definable in the language of rings. This answers a question of Krapp, Kuhlmann, and Link.
Explore related subjects
Keep this discovery
Blaise Boissonneau, Anna De Mase, Franziska Jahnke, Pierre Touchard. 2025-12-04. Growing Spines: Ad Infinitum et Ad Infinitesimalia. https://arxiv.org/abs/2512.04932
Cite the original work for its findings. Save a collection to share your selection of sources.