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Related papers: A note on NSOP$_{1}$ in one variable

200 papers

We give an example of an SOP theory $T$, such that any $L(M)$-formula $\varphi(x,y)$ with $|y|=1$ is NSOP. We show that any such $T$ must have the independence property. We also give a simplified proof of Lachlan's theorem that if every…

Logic · Mathematics 2025-07-15 Will Johnson

A theory is NIP (resp. stable) if and only if every formula with parameters in two single variables is NIP (resp. does not have the order property).

Logic · Mathematics 2021-03-30 Pierre Simon

Answering a question of Dobrowolski, Kim and Ramsey, we find an $\mathrm{NSOP}_{1}$ theory that does not satisfy the existence axiom.

Logic · Mathematics 2024-07-19 Scott Mutchnik

Answering a question of D\v{z}amonja and Shelah, we show that every NSOP$_2$ theory is NSOP$_1$.

Logic · Mathematics 2023-06-16 Scott Mutchnik

In this paper, we introduce a concept of non-dependence of variables in formulas. A formula in first-order logic is non-dependent of a variable if the truth value of this formula does not depend on the value of that variable. This variable…

Logic · Mathematics 2025-01-29 Koen Lefever , Gergely Székely

The main purpose of this paper is to present a new and more uniform model-theoretic/combinatorial proof of the theorem ([5]): The randomization $T^{R}$ of a complete first-order theory $T$ with $NIP$ is a (complete) first-order continuous…

Logic · Mathematics 2026-01-01 Karim Khanaki , Massoud Pourmahdian

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

A type analysable in one-based types in a simple theory is itself one-based.

Logic · Mathematics 2019-04-15 Frank Olaf Wagner

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

We introduce a combinatorial criterion for verifying whether a formula is not the conjunction of an equation and a co-equation. Using this, we give a proof for the nonequationality of the free group. Furthermore, we generalize the latter…

Logic · Mathematics 2023-03-08 Isabel Müller , Rizos Sklinos

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

This paper continues math.LO/0009087. We present a rank function for NSOP_1 theories and give an example of a theory which is NSOP_1 but not simple. We also investigate the connection between maximality in the ordering <^* among complete…

Logic · Mathematics 2007-05-23 Saharon Shelah , Alex Usvyatsov

We prove the existence of a model companion of the two-sorted theory of $c$-nilpotent Lie algebras over a field satisfying a given theory of fields. We describe a language in which it admits relative quantifier elimination up to the field…

Logic · Mathematics 2025-07-18 Christian d'Elbée , Isabel Müller , Nicholas Ramsey , Daoud Siniora

A relevant thesis is that for the family of complete first order theories with NIP (i.e. without the independence property) there is a substantial theory, like the family of stable (and the family of simple) first order theories. We examine…

Logic · Mathematics 2007-05-23 Saharon Shelah

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

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

We show that the sum of two free random variables can have a free Poisson law without any of them having a free Poisson law.

Operator Algebras · Mathematics 2007-05-23 Florent Benaych-Georges

We answer a question of Pakhomov by showing that there is a consistent, c.e. theory $T$ such that no theory which is definitionally equivalent to $T$ has a computable model. A key tool in our proof is the model-theoretic notion of mutual…

Logic · Mathematics 2023-09-22 Patrick Lutz , James Walsh

We give a new characterization of $SOP$ (the strict order property) in terms of the behaviour of formulas in any model of the theory as opposed to having to look at the behaviour of indiscernible sequences inside saturated ones. We refine a…

Logic · Mathematics 2022-03-23 Karim Khanaki
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