English
Related papers

Related papers: A note on some example of NSOP1 theories

200 papers

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 adapt the properties of Kim-independence in NSOP1 theories with existence proven in [5],[4] and [2] by Ramsey, Kaplan, Chernikov, Dobrowolski and Kim to hyperimaginaries by adding the assumption of existence for hyperimaginaries. We show…

Logic · Mathematics 2022-10-26 Yvon Bossut

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

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 prove several results on the behavior of Kim-independence upon changing the base in NSOP$_{1}$ theories. As a consequence, we prove that Kim-independence satisfies transitivity and that this characterizes NSOP$_{1}$. Moreover, we…

Logic · Mathematics 2020-12-08 Itay Kaplan , Nicholas Ramsey

We define weak stable Kim-forking, a notion that generalizes stable forking to the context of NSOP1 theories. We adapt some of the known results on stable forking to this context.

Logic · Mathematics 2025-11-03 Yvon Bossut

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

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

In this work we study some examples of groups definable and type-definable in NSOP1 theories. We exhibit some behaviors of these groups that differ from the ones of simple groups. We take interest in the notions of generics and stabilizers,…

Logic · Mathematics 2025-10-31 Yvon Bossut

We provide a partial answer to a question asked independently by Kim and d'Elb\'ee and show that, under the assumption of the stable Kim-forking conjecture, every $\mathrm{NSOP}_1$ rosy theory must be simple. We also prove that the theory…

Logic · Mathematics 2026-01-14 Alberto Miguel-Gómez

We show that NSOP$_{1}$ theories are exactly the theories in which Kim-independence satisfies a form of local character. In particular, we show that if $T$ is NSOP$_{1}$, $M\models T$, and $p$ is a type over $M$, then the collection of…

Logic · Mathematics 2018-02-13 Itay Kaplan , Nicholas Ramsey , Saharon Shelah

We introduce a family of local ranks DQ depending on a finite set Q of pairs of the form (\varphi(x,y),q(y)) where \varphi(x,y) is a formula and q(y) is a global type. We prove that in any NSOP1 theory these ranks satisfy some desirable…

Logic · Mathematics 2021-11-04 Jan Dobrowolski , Daniel Max Hoffmann

We show that Kim-forking satisfies existence in all NSOP$_1$ theories.

Logic · Mathematics 2025-12-30 Byunghan Kim , Joonhee Kim , Hyoyoon Lee

We prove some results about the theory of independence in $\mathrm{NSOP}_{3}$ theories that do not hold in $\mathrm{NSOP}_{4}$ theories. We generalize Chernikov's work on simple and co-simple types in $\mathrm{NTP}_{2}$ theories to types…

Logic · Mathematics 2026-05-29 Scott Mutchnik

Tree properties are introduced by Shelah, and it is well-known that a theory has TP (the tree property) if and only if it has TP$_1$ or TP$_2$. In any simple theory (i.e., a theory not having TP), forking supplies a good independence notion…

Logic · Mathematics 2019-07-05 Enrique Casanovas , Byunghan Kim

We develop the theory of Kim-independence in the context of NSOP$_{1}$ theories satsifying the existence axiom. We show that, in such theories, Kim-independence is transitive and that $\ind^{K}$-Morley sequences witness Kim-dividing. As…

Logic · Mathematics 2023-06-05 Artem Chernikov , 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

In the classification of complete first-order theories, many dividing lines have been defined in order to understand the complexity and the behavior of some classes of theories. In this paper, using the concept of patterns of consistency…

Logic · Mathematics 2025-07-08 Michele Bailetti

We initiate the study of a generalization of Kim-independence, Conant-independence, based on the "strong Kim-dividing" of Kaplan, Ramsey and Shelah. We introduce an axiom on stationary independence relations essentially generalizing the…

Logic · Mathematics 2024-01-26 Scott Mutchnik

We study expansions of NSOP$_1$ theories that preserve NSOP$_1$. We prove that if $T$ is a model complete NSOP$_1$ theory eliminating the quantifier $\exists^{\infty}$, then the generic expansion of $T$ by arbitrary constant, function, and…

Logic · Mathematics 2018-09-18 Alex Kruckman , Nicholas Ramsey
‹ Prev 1 2 3 10 Next ›