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Related papers: Wild theories with o-minimal open core

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We introduce the notions of triviality and order-triviality for global invariant types in an arbitrary first-order theory and show that they are well behaved in the NIP context. We show that these two notions agree for invariant global…

Logic · Mathematics 2026-02-24 Slavko Moconja , Predrag Tanović

In this short note we show that if we add predicate for a dense complete indiscernible sequence in a dependent theory then the result is still dependent. This answers a question of Baldwin and Benedikt and implies that every unstable…

Logic · Mathematics 2009-06-16 Artem Chernikov , Pierre Simon

This paper answers several open questions around structures with o-minimal open core. We construct an expansion of an o-minimal structure $\mathcal{R}$ by a unary predicate such that its open core is a proper o-minimal expansion of…

Logic · Mathematics 2021-01-08 Alexi Block Gorman , Erin Caulfield , Philipp Hieronymi

Let $\mathcal M=\langle M, <, +, \dots\rangle$ be an o-minimal expansion of an ordered group, and $P\subseteq M$ a dense set such that certain tameness conditions hold. We introduce the notion of a `product cone' in $\widetilde{\mathcal…

Logic · Mathematics 2017-08-15 Pantelis E. Eleftheriou

We generalize the Unstable Formula Theorem characterization of stable theories from \citep{sh78}: that a theory $T$ is stable just in case any infinite indiscernible sequence in a model of $T$ is an indiscernible set. We use a generalized…

Logic · Mathematics 2013-03-15 Lynn Scow

Let $\mathbb{T}$ be the differential field of logarithmic-exponential transseries. We show that the expansion of $\mathbb{T}$ by its natural exponential function is model complete and locally o-minimal. We give an axiomatization of the…

Logic · Mathematics 2020-11-30 Elliot Kaplan

We prove the following theorem: let $\widetilde{\mathcal R}$ be an expansion of the real field $\overline{\mathbb R}$, such that every definable set (I) is a uniform countable union of semialgebraic sets, and (II) contains a "semialgebraic…

Logic · Mathematics 2018-12-27 Pantelis E. Eleftheriou , Alex Savatovsky

The wild group is the group of wild automorphisms of a local field of characteristic p. In this paper we apply Fontaine-Wintenberger's theory of fields of norms to study the structure of the wild group. In particular we provide a new short…

Group Theory · Mathematics 2007-05-23 Ivan Fesenko

This paper investigates expansions of distal structures by a unary subset that arises as the image of a projection map. We first provide a sufficient condition for such an expansion to remain distal. Based on this criterion, we establish…

Logic · Mathematics 2026-03-23 Koki Okura

We prove several structural results on definably compact groups G in o-minimal expansions of real closed fields, such as (i) G is definably an almost direct product of a semisimple group and a commutative group, and (ii) the group (G, .) is…

Logic · Mathematics 2008-11-04 Ehud Hrushovski , Ya'acov Peterzil , Anand Pillay

A subset of a topological space is constructible if it is a finite Boolean combination of closed sets. We prove that every NTP$_2$ expansion of $(\mathbb{R},<,+)$ by constructible sets defines only constructible sets, and that definable…

Logic · Mathematics 2026-05-20 Pablo Andújar Guerrero

We give sufficient conditions for a predicate P in a complete theory T to be stably embedded: P with its induced 0-definable structure has "finite rank", P has NIP in T and P is 1-stably embedded. This generalizes recent work by Hasson and…

Logic · Mathematics 2010-01-05 Anand Pillay

We study the model theory of covers of groups definable in o-minimal structures. This includes the case of covers of compact real Lie groups. In particular we study categoricity questions, pointing out some notable differences with the case…

Logic · Mathematics 2010-09-28 Alessandro Berarducci , Ya'acov Peterzil , Anand Pillay

We prove Zilber's Trichotomy Conjecture for strongly minimal expansions of two-dimensional groups, definable in o-minimal structures: Theorem. Let M be an o-minimal expansion of a real closed field, (G;+) a 2-dimensional group definable in…

Logic · Mathematics 2021-04-13 Pantelis Eleftheriou , Assaf Hasson , Ya'acov Peterzil

We study directed sets definable in o-minimal structures, showing that in expansions of ordered fields these admit cofinal definable curves, as well as a suitable analogue in expansions of ordered groups, and furthermore that no analogue…

Logic · Mathematics 2021-09-17 Pablo Andujar Guerrero , Margaret E. M. Thomas , Erik Walsberg

We first show that the projection image of a discrete definable set is again discrete for an arbitrary definably complete locally o-minimal structure. This fact together with the results in a previous paper implies tame dimension theory and…

Logic · Mathematics 2022-10-07 Masato Fujita , Tomohiro Kawakami , Wataru Komine

We show that a complete first-order theory $T$ is distal provided it has a model $M$ such that the theory of the Shelah expansion of $M$ is distal.

Logic · Mathematics 2019-11-26 Gareth Boxall , Charlotte Kestner

The Tits core G^+ of a totally disconnected locally compact group G is defined as the abstract subgroup generated by the closures of the contraction groups of all its elements. We show that a dense subgroup is normalised by the Tits core if…

Group Theory · Mathematics 2014-05-15 Pierre-Emmanuel Caprace , Colin D. Reid , George A. Willis

Let K be an algebraically bounded structure and T be its theory. If T is model complete, then the theory of K endowed with a derivation, denoted by $T^{\delta}$, has a model completion. Additionally, we prove that if the theory T is…

Logic · Mathematics 2024-11-14 Fornasiero Antongiulio , Terzo Giuseppina

We answer in the affirmative a conjecture of Berarducci, Peterzil and Pillay \cite{BPP10} for solvable groups, which is an o-minimal version of a particular case of Milnor's isomorphism conjecture \cite{jM83}. We prove that every abstract…

Logic · Mathematics 2025-03-27 Elías Baro , Daniel Palacín