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We use a known example of an algebraically maximal discretely valued field of positive characteristic $p$ which admits purely inseparable extensions of degree $p^2$ with defect $p$ to construct algebraically maximal valued fields of…

Commutative Algebra · Mathematics 2026-01-09 Franz-Viktor Kuhlmann

The main purpose of the paper is to establish a closedness theorem over Henselian valued fields $K$ of equicharacteristic zero (not necessarily algebraically closed) with separated analytic structure. It says that every projection with a…

Algebraic Geometry · Mathematics 2018-01-09 Krzysztof Jan Nowak

Given a henselian valuation, we study its definability (with and without parameters) by examining conditions on the value group. We show that any henselian valuation whose value group is not closed in its divisible hull is definable in the…

Logic · Mathematics 2022-06-16 Lothar Sebastian Krapp , Salma Kuhlmann , Moritz Link

We study subfields of large fields which are generated by infinite existentially definable subsets. We say that such subfields are existentially generated. Let $L$ be a large field of characteristic exponent $p$, and let $E\subseteq L$ be…

Logic · Mathematics 2017-10-11 Sylvy Anscombe

We use cell decomposition techniques to study additive reducts of p- adic fields. We consider a very general class of fields, including fields with infinite residue fields, which we study using a multi-sorted language. The results are used…

Logic · Mathematics 2012-05-21 Eva Leenknegt

A henselian valued field $K$ is called a tame field if its algebraic closure $\tilde{K}$ is a tame extension, that is, the ramification field of the normal extension $\tilde{K}|K$ is algebraically closed. Every algebraically maximal…

Commutative Algebra · Mathematics 2014-07-15 Franz-Viktor Kuhlmann

Given a perfectoid field, we find an elementary extension and a henselian defectless valuation on it, whose value group is divisible and whose residue field is an elementary extension of the tilt. This specializes to the almost purity…

Commutative Algebra · Mathematics 2025-03-13 Franziska Jahnke , Konstantinos Kartas

We introduce a notion of valued module which is suitable to study valued fields of positive characteristic. Then we built-up a robust theory of henselianity in the language of valued modules and prove Ax-Kochen Ershov type results.

Logic · Mathematics 2016-05-05 Gönenç Onay

In this note we study sets of NIP formulas in some theories of fields and valued fields, with a special focus on the sets of quantifier-free and existential formulas. First, we give a new proof of the fact that Separably Closed Valued…

Logic · Mathematics 2026-02-04 Paulo Andrés Soto Moreno

We give a criterion for maps on ultrametric spaces to be surjective and to preserve spherical completeness. We show how Hensel's Lemma and the multi-dimensional Hensel's Lemma follow from our result. We give an easy proof that the latter…

Commutative Algebra · Mathematics 2013-04-02 Franz-Viktor Kuhlmann

We give explicit formulas witnessing IP, \IPn or TP2 in fields with Artin-Schreier extensions. We use them to control $p$-extensions of mixed characteristic henselian valued fields, allowing us most notably to generalize to the \NIPn…

Logic · Mathematics 2024-09-20 Blaise Boissonneau

A field is existentially t-henselian if it is has the same existential theory in the first-order language of rings as a field that admits a nontrivial henselian valuation. This property turns out to be equivalent to $\mathbb{Z}$-largeness,…

Logic · Mathematics 2026-04-02 Sylvy Anscombe

We study the algebraic implications of the non-independence property (NIP) and variants thereof (dp-minimality) on infinite fields, motivated by the conjecture that all such fields which are neither real closed nor separably closed admit a…

Logic · Mathematics 2018-12-05 Katharina Dupont , Assaf Hasson , Salma Kuhlmann

In this paper, we undertake a systematic model and valuation theoretic study of the class of ordered fields which are dense in their real closure. We apply this study to determine definable henselian valuations on ordered fields, in the…

Logic · Mathematics 2021-07-21 Lothar Sebastian Krapp , Salma Kuhlmann , Gabriel Lehéricy

We consider four properties of a field $K$ related to the existence of (definable) henselian valuations on $K$ and on elementarily equivalent fields, and study the implications between them. Surprisingly, the full pictures look very…

Logic · Mathematics 2015-12-16 Sylvy Anscombe , Franziska Jahnke

The paper establishes a relationship between finite separable extensions and norm groups of strictly quasilocal fields with Henselian discrete valuations, which yields a generally nonabelian one-dimensional local class field theory.

Rings and Algebras · Mathematics 2007-05-23 I. D. Chipchakov

We show that every valued differential field has an immediate strict extension that is spherically complete. We also discuss the issue of uniqueness up to isomorphism of such an extension.

Commutative Algebra · Mathematics 2018-04-18 Matthias Aschenbrenner , Lou van den Dries , Joris van der Hoeven

This paper develops algebraic geometry over Henselian real valued (i.e. of rank 1) fields $K$, being a sequel to our paper about that over Henselian discretely valued fields. Several results are given including: a certain concept of fiber…

Algebraic Geometry · Mathematics 2016-08-30 Krzysztof Jan Nowak

In this article we further develop the theory of valuation independence and study its relation with classical notions in valuation theory such as immediate and defectless extensions. We use this general theory to settle two open questions…

Commutative Algebra · Mathematics 2018-03-28 Anna Blaszczok , Pablo Cubides Kovacsics , Franz-Viktor Kuhlmann

In this paper, a method for constructing a near optimal normal basis for algebraic extensions of a finite field is described. In each extension, except for the squares of basis elements, the product of two distinct normal basis elements can…

General Mathematics · Mathematics 2021-06-29 Duggirala Meher Krishna , Duggirala Ravi