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Related papers: Non-forking independence in stable theories

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We develop the theory of generically stable types, independence relation based on nonforking and stable weight in the context of dependent (NIP) theories.

Logic · Mathematics 2008-02-01 Alexander Usvyatsov

We study NSOP$_{1}$ theories. We define Kim-independence, which generalizes non-forking independence in simple theories and corresponds to non-forking at a generic scale. We show that Kim-independence satisfies a version of Kim's lemma,…

Logic · Mathematics 2019-01-09 Itay Kaplan , Nicholas Ramsey

Forking is a central notion of model theory, generalizing linear independence in vector spaces and algebraic independence in fields. We develop the theory of forking in abstract, category-theoretic terms, for reasons both practical (we…

Logic · Mathematics 2019-02-19 Michael Lieberman , Jiří Rosický , Sebastien Vasey

In the first part of this work the notion of stable Kim-forking is discussed and some context on this matter is given. In the second part a general way of building some examples of NSOP1 theories as the limit of some Fraisse class…

Logic · Mathematics 2025-10-31 Yvon Bossut

We provide a differential-algebraic description of forking independence in the stable theory DCF$_{p,m}$ of differentially closed fields of characteristic $p>0$ with $m$-many commuting derivations. As a by-product of this description, we…

Logic · Mathematics 2025-11-10 Piotr Kowalski , Omar León Sánchez , Amador Martin-Pizarro

We study Kim-independence over arbitrary sets. Assuming that forking satisfies existence, we establish Kim's lemma for Kim-dividing over arbitrary sets in an NSOP$_{1}$ theory. We deduce symmetry of Kim-independence and the independence…

Logic · Mathematics 2019-09-19 Jan Dobrowolski , Byunghan Kim , Nicholas Ramsey

We characterize nonforking (Morley) sequences in dependent theories in terms of a generalization of Poizat's special sequences and show that average types of Morley sequences are stationary over their domains. We characterize generically…

Logic · Mathematics 2008-10-07 Alexander Usvyatsov

A new notion of independence relation is given and associated to it, the class of flat theories, a subclass of strong stable theories including the superstable ones is introduced. More precisely, after introducing this independence…

Logic · Mathematics 2018-04-18 Daniel Palacín , Saharon Shelah

We prove that in theories without the tree property of the second kind (which include dependent and simple theories) forking and dividing over models are the same, and in fact over any extension base. As an application we show that…

Logic · Mathematics 2011-03-22 Artem Chernikov , Itay Kaplan

An important dividing line in the class of unstable theories is being NSOP$_1$, which is more general than being simple. In NSOP$_1$ theories forking independence may not be as well-behaved as in stable or simple theories, so it is replaced…

Logic · Mathematics 2023-03-29 Jan Dobrowolski , Mark Kamsma

We presents an independence relation on sets, one can define dimension by it, assuming that we have an abstract elementary class with a forking notion that satisfies the axioms of a good frame minus stability.

Logic · Mathematics 2011-05-19 Adi Jarden , Alon Sitton

Kim's Lemma is a key ingredient in the theory of forking independence in simple theories. It asserts that if a formula divides, then it divides along every Morley sequence in type of the parameters. Variants of Kim's Lemma have formed the…

Logic · Mathematics 2024-08-14 Alex Kruckman , Nicholas Ramsey

This course introduces the fruitful links between model theory and a combinatoric of sets given by independence relations. An independence relation on a set is a ternary relation between subsets. Chapter 1 should be considered as an…

Logic · Mathematics 2025-01-28 Christian d'Elbée

We develop a new notion of independence suggested by Scanlon (th-independence). We prove that in a large class of theories (which includes all simple theories) this notion has many of the properties needed for an adequate geometric…

Logic · Mathematics 2007-05-23 Alf Onshuus

We investigate the notions of strict independence and strict non-forking, and establish basic properties and connections between the two. In particular it follows from our investigation that in resilient theories strict non-forking is…

Logic · Mathematics 2014-10-01 Itay Kaplan , Alexander Usvyatsov

We study one way in which stable phenomena can exist in an NIP theory. We start by defining a notion of 'pure instability' that we call 'distality' in which no such phenomenon occurs. O-minimal theories and the p-adics for example are…

Logic · Mathematics 2015-09-24 Pierre Simon

A dependent theory is a (first order complete theory) T which does not have the independence property. A main result here is: if we expand a model of T by the traces on it of sets definable in a bigger model then we preserve its being…

Logic · Mathematics 2013-02-20 Saharon Shelah

Monadic stability and the more general monadic dependence (or NIP) are tameness conditions for classes of logical structures, studied in the 80's in Shelah's classification program in model theory. They recently emerged in algorithmic and…

Logic in Computer Science · Computer Science 2025-05-23 Wojciech Przybyszewski , Szymon Toruńczyk

We establish several results regarding dividing and forking in NTP2 theories. We show that dividing is the same as array-dividing. Combining it with existence of strictly invariant sequences we deduce that forking satisfies the chain…

Logic · Mathematics 2013-08-14 Itaï Ben Yaacov , Artem Chernikov

We initiate a systematic study of \emph{generic stability independence} and introduce the class of \emph{treeless theories} in which this notion of independence is particularly well-behaved. We show that the class of treeless theories…

Logic · Mathematics 2023-05-30 Itay Kaplan , Nicholas Ramsey , Pierre Simon
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