English

Approximation theorems for spaces of localities

Commutative Algebra 2021-02-16 v2 Number Theory

Abstract

The classical Artin--Whaples approximation theorem allows to simultaneously approximate finitely many different elements of a field with respect to finitely many pairwise inequivalent absolute values. Several variants and generalizations exist, for example for finitely many (Krull) valuations, where one usually requires that these are independent, i.e. induce different topologies on the field. Ribenboim proved a generalization for finitely many valuations where the condition of independence is relaxed for a natural compatibility condition, and Ershov proved a statement about simultaneously approximating finitely many different elements with respect to finitely many possibly infinite sets of pairwise independent valuations. We prove approximation theorems for infinite sets of valuations and orderings without requiring pairwise independence.

Keywords

Cite

@article{arxiv.1901.02632,
  title  = {Approximation theorems for spaces of localities},
  author = {Sylvy Anscombe and Philip Dittmann and Arno Fehm},
  journal= {arXiv preprint arXiv:1901.02632},
  year   = {2021}
}

Comments

Correction of typographical errors, simplified exposition in the last two sections

R2 v1 2026-06-23T07:06:47.432Z