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Related papers: Dp-finite fields IV: the rank 2 picture

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We continue our earlier investigation of dp-finite fields. We show that the "heavy sets" of [6] are exactly the sets of full dp-rank. As a consequence, full dp-rank is a definable property in definable families of sets. If $I$ is the group…

Logic · Mathematics 2019-10-18 Will Johnson

In this note we reproduce Johnson's analysis of $W_2$-topologies on fields of characteristic 2, which was originally stated for fields of characteristic different than 2. Following his framework, we prove that the canonical topology of an…

Logic · Mathematics 2025-12-10 Paulo Andrés Soto Moreno

We prove that unstable dp-finite fields admit definable V-topologies. As a consequence, the henselianity conjecture for dp-finite fields implies the Shelah conjecture for dp-finite fields. This gives a conceptually simpler proof of the…

Logic · Mathematics 2020-05-01 Will Johnson

We prove the dp-finite case of the Shelah conjecture on NIP fields. If K is a dp-finite field, then K admits a non-trivial definable henselian valuation ring, unless K is finite, real closed, or algebraically closed. As a consequence, the…

Logic · Mathematics 2020-05-29 Will Johnson

We show that dp-minimal valued fields are henselian and that a dp-minimal field admitting a definable type V topology is either real closed, algebraically closed or admits a non-trivial definable henselian valuation. We give classifications…

Logic · Mathematics 2015-07-15 Franziska Jahnke , Pierre Simon , Erik Walsberg

We prove that NIP valued fields of positive characteristic are henselian. Furthermore, we partially generalize the known results on dp-minimal fields to dp-finite fields. We prove a dichotomy: if K is a sufficiently saturated dp-finite…

Logic · Mathematics 2020-01-16 Will Johnson

We initiate the study of definable V-topolgies and show that there is at most one such V-topology on a t-henselian NIP field. Equivalently, we show that if $(K,v_1,v_2)$ is a bi-valued NIP field with $v_1$ henselian (resp. t-henselian) then…

Logic · Mathematics 2019-02-15 Yatir Halevi , Assaf Hasson , Franziska Jahnke

We obtain some new results on the topology of unary definable sets in densely ordered Abelian groups of burden groups of burden 2. In the special case in which the structure has dp-rank 2, we show that the existence of an infinite definable…

Logic · Mathematics 2022-11-21 Alfred Dolich , John Goodrick

We are concerned with topology of Hensel minimal structures on non-trivially valued fields $K$, whose axiomatic theory was introduced in a recent paper by Cluckers-Halupczok-Rideau. We additionally require that every definable subset in the…

Algebraic Geometry · Mathematics 2024-12-10 Krzysztof Jan Nowak

We introduce the notion of the definable rank of an ordered field, ordered abelian group and ordered set, respectively. We study the relation between the definable rank of an ordered field and the definable rank of the value group of its…

Logic · Mathematics 2026-01-13 Lothar Sebastian Krapp , Salma Kuhlmann , Lasse Vogel

In his unpublished preprint "Definable Valuations" Koenigsmann shows that every field that admits a t-henselian topology is either real closed or separably closed or admits a definable valuation inducing the t-henselian topology. To show…

Logic · Mathematics 2016-03-31 Katharina Dupont

We study the question of $\mathcal{L}_{\mathrm{ring}}$-definability of non-trivial henselian valuation rings. Building on previous work of Jahnke and Koenigsmann, we provide a characterization of henselian fields that admit a non-trivial…

Logic · Mathematics 2025-11-12 Margarete Ketelsen , Simone Ramello , Piotr Szewczyk

We develop tame topology over dp-minimal structures equipped with definable uniformities satisfying certain assumptions. Our assumptions are enough to ensure that definable sets are tame: there is a good notion of dimension on definable…

Logic · Mathematics 2019-09-18 Pierre Simon , Erik Walsberg

We develop a notion of (principal) differential rank for differential-valued fields, in analog of the exponential rank and of the difference rank. We give several characterizations of this rank. We then give a method to define a derivation…

Commutative Algebra · Mathematics 2018-10-26 Salma Kuhlmann , Gabriel Lehéricy

Admitting a non-trivial $p$-henselian valuation is a weaker assumption on a field than admitting a non-trivial henselian valuation. Unlike henselianity, $p$-henselianity is an elementary property in the language of rings. We are interested…

Logic · Mathematics 2014-11-26 Franziska Jahnke , Jochen Koenigsmann

We give an explicit algebraic characterisation of all definable henselian valuations on a dp-minimal real field. Additionally we characterise all dp-minimal real fields that admit a definable henselian valuation with real closed residue…

Logic · Mathematics 2024-10-15 Lothar Sebastian Krapp , Salma Kuhlmann , Lasse Vogel

Definable topological groups whose topologies are affine have definable $\mathcal C^r$ structures in d-minimal expansions of ordered fields, where $r$ is a positive integer. We prove this fact using a new notion called partition degree of a…

Logic · Mathematics 2024-07-24 Masato Fujita

For certain theories of existentially closed topological differential fields, we show that there is a strong relationship between $\mathcal L\cup\{D\}$-definable sets and their $\mathcal L$-reducts, where $\mathcal L$ is a relational…

Logic · Mathematics 2017-07-26 Françoise Point

We prove some technical results on definable types in $p$-adically closed fields, with consequences for definable groups and definable topological spaces. First, the code of a definable $n$-type (in the field sort) can be taken to be a real…

Logic · Mathematics 2024-07-18 Pablo Andujar Guerrero , Will Johnson

Let $T$ be a theory which is t-minimal, meaning that with respect to some definable topology, a unary definable set $D \subseteq M$ has non-empty interior iff it is infinite. If $K$ is a definable field in $T$, then $K$ is finite or "large"…

Logic · Mathematics 2026-05-11 Will Johnson
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