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Related papers: The theory of maximal Hardy fields

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We show that all maximal Hardy fields are elementarily equivalent as differential fields, and give various applications of this result and its proof. We also answer some questions on Hardy fields posed by Boshernitzan.

Logic · Mathematics 2025-02-18 Matthias Aschenbrenner , Lou van den Dries , Joris van der Hoeven

We discuss the conjecture that every maximal Hardy field has the Intermediate Value Property for differential polynomials, and its equivalence to the statement that all maximal Hardy field are elementarily equivalent to the differential…

Logic · Mathematics 2019-04-03 Matthias Aschenbrenner , Lou van den Dries , Joris van der Hoeven

We show that maximal analytic Hardy fields are $\eta_1$ in the sense of Hausdorff. We also prove various embedding theorems about analytic Hardy fields. For example, the ordered differential field $\mathbb T$ of transseries is shown to be…

Logic · Mathematics 2025-09-16 Matthias Aschenbrenner , Lou van den Dries

Let $\mathbb{T}$ be the differential field of logarithmic-exponential transseries. We consider the expansion of $\mathbb{T}$ by the binary map that sends a real number $r$ and a positive transseries $f$ to the transseries $f^r$. Building on…

Logic · Mathematics 2024-12-24 Elliot Kaplan

Every maximal Hardy field has a proper elementary differential subfield that is Dedekind complete in the maximal Hardy field. This pair of Hardy fields is a transserial tame pair, shown to have a complete and model complete elementary…

Logic · Mathematics 2025-09-10 Nigel Pynn-Coates

We show how to fill "countable" gaps in Hardy fields. We use this to prove that any two maximal Hardy fields are back-and-forth equivalent.

Logic · Mathematics 2024-06-19 Matthias Aschenbrenner , Lou van den Dries , Joris van der Hoeven

We study relative differential closure in the context of Hardy fields. Using our earlier work on algebraic differential equations over Hardy fields, this leads to a proof of a conjecture of Boshernitzan (1981): the intersection of all…

Logic · Mathematics 2026-04-27 Matthias Aschenbrenner , Lou van den Dries , Joris van der Hoeven

We show that every Hardy field extends to an $\omega$-free Hardy field. This result relates to classical oscillation criteria for second-order homogeneous linear differential equations. It is essential in [10], and here we apply it to…

Commutative Algebra · Mathematics 2026-03-11 Matthias Aschenbrenner , Lou van den Dries , Joris van der Hoeven

We define the universal exponential extension of an algebraically closed differential field and investigate its properties in the presence of a nice valuation and in connection with linear differential equations. Next we prove normalization…

Commutative Algebra · Mathematics 2026-04-28 Matthias Aschenbrenner , Lou van den Dries , Joris van der Hoeven

We show that the natural embedding of the differential field of transseries into Conway's field of surreal numbers with the Berarducci-Mantova derivation is an elementary embedding. We also prove that any Hardy field embeds into the field…

Logic · Mathematics 2016-08-12 Matthias Aschenbrenner , Lou van den Dries , Joris van der Hoeven

This paper concerns pairs of models of the theory of the differential field of logarithmic-exponential transseries that are tame as a pair of real closed fields. That is, the smaller model is bounded inside the larger model and there exists…

Logic · Mathematics 2024-08-14 Nigel Pynn-Coates

In this paper we prove sharp Hardy inequalities by using Maximal function theory. Our results improve and extend the well-known results of G.Hardy \cite{Ha04}, T.Cazenave \cite {Ca03}, J.-Y.Chemin\cite {Ch06} and T.Tao\cite {TT06}.

Analysis of PDEs · Mathematics 2007-05-23 Jia Yuan , Junyong Zhang

We introduce the notion of differential largeness for fields equipped with several commuting derivations (as an analogue to largeness of fields). We lay out the foundations of this new class of "tame" differential fields. We state several…

Algebraic Geometry · Mathematics 2024-02-07 Omar León Sánchez , Marcus Tressl

The present article surveys surreal numbers with an informal approach, from their very first definition to their structure of universal real closed analytic and exponential field. Then we proceed to give an overview of the recent…

Logic · Mathematics 2017-11-09 Vincenzo Mantova , Mickaël Matusinski

The differential field of transseries extends the field of real Laurent series, and occurs in various context: asymptotic expansions, analytic vector fields, o-minimal structures, to name a few. We give an overview of the algebraic and…

Logic · Mathematics 2016-02-10 Matthias Aschenbrenner , Lou van den Dries , Joris van der Hoeven

Let $T$ be a polynomially bounded o-minimal theory extending the theory of real closed ordered fields. Let $K$ be a model of $T$ equipped with a $T$-convex valuation ring and a $T$-derivation. If this derivation is continuous with respect…

Logic · Mathematics 2023-03-08 Elliot Kaplan

We provide a characterisation of differentially large fields in arbitrary characteristic and a single derivation in the spirit of Blum axioms for differentially closed fields. In the case of characteristic zero, we use these axioms to…

Algebraic Geometry · Mathematics 2024-12-25 Omar León Sánchez , Marcus Tressl

We give a version of the Montel theorem for Hardy spaces of holomorphic functions on an infinite dimensional space. As a by-product, we provide a Montel-type theorem for the Hardy space of Dirichlet series. This approach also gives an…

Functional Analysis · Mathematics 2020-04-23 Tomás Fernández Vidal , Daniel Galicer , Pablo Sevilla-Peris

We study the existence of formal Taylor expansions for functions defined on fields of generalised series. We prove a general result for the existence and convergence of those expansions for fields equipped with a derivation and an…

Logic · Mathematics 2025-09-11 Vincent Bagayoko , Vincenzo Mantova

Let $T$ be a complete theory of fields, possibly with extra structure. Suppose that model-theoretic algebraic closure agrees with field-theoretic algebraic closure, or more generally that model-theoretic algebraic closure has the exchange…

Logic · Mathematics 2023-06-28 Will Johnson , Jinhe Ye
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