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Related papers: NSOP$_1$-like independence in AECats

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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

For an $\omega$-categorical theory $T$ and model $\mathcal{M}$ of $T$ we define a hierarchy of ranks, the $n$-ranks for $n < \omega$ which only care about imaginary elements ``up to level $n$'', where level $n$ contains every element of $M$…

Logic · Mathematics 2026-05-28 Vera Koponen

In this paper we give characterizations of the super-stable theories, in terms of an external property called representation. In the sense of the representation property, the mentioned class of first-order theories can be regarded as "not…

Logic · Mathematics 2019-04-18 Saharon Shelah

We develop a comprehensive theory of the stable representation categories of several sequences of groups, including the classical and symmetric groups, and their relation to the unstable categories. An important component of this theory is…

Representation Theory · Mathematics 2015-06-17 Steven V Sam , Andrew Snowden

We study the spaces of locally-finite stability conditions on the derived categories of coherent sheaves on the minimal resolutions of $A_n$-singularities supported at the exceptional sets. Our main theorem is that they are connected and…

Algebraic Geometry · Mathematics 2010-04-20 Akira Ishii , Kazushi Ueda , Hokuto Uehara

The Univalent Foundations requires a logic that allows us to define structures on homotopy types, similar to how first-order logic with equality ($\text{FOL}_=$) allows us to define structures on sets. We develop the syntax, semantics and…

Logic · Mathematics 2017-09-27 Dimitris Tsementzis

We classify the stable formulas in the theory of Dense Linear Orders without endpoints, the stable formulas in the theory of Divisible Abelian Groups, and the stable formulas without parameters in the theory of Real Closed Fields. The third…

Logic · Mathematics 2024-10-24 Daniel Max Hoffmann , Chieu-Minh Tran , Jinhe Ye

We rewrite simplicially the standard definitions of a complete first order theory, a model of it, and various characterisations of stability of a complete first order theory. In our reformulations the simplicial language replaces the…

Category Theory · Mathematics 2025-10-02 Misha Gavrilovich

We consider the first-order theory of random variables with the probabilistic independence relation, which concerns statements consisting of random variables, the probabilistic independence symbol, logical operators, and existential and…

Information Theory · Computer Science 2021-08-18 Cheuk Ting Li

An axiomatic treatment of `independence relations' (notions of independence) for complete first-order theories is presented, the principal examples being forking (due to Shelah) and thorn-forking (due to Onshuus). Thorn-forking is…

Logic · Mathematics 2007-05-23 Hans Adler

We propose a semantic foundation for logics for reasoning in settings that possess a distinction between equality of variables, a coarser equivalence of variables, and a notion of conditional independence between variables. We show that…

Logic in Computer Science · Computer Science 2026-05-18 Alex Simpson

We study stable like behaviour in first order theories without the independence property. We introduce generically stable measures, give characterizatiions, and show their ubiquity. We also introduce generic compact domination. We also…

Logic · Mathematics 2010-02-26 Ehud Hrushovski , Anand Pillay , Pierre Simon

Let $G$ be an acylic directed graph. For each vertex $g \in G$, we define an involution on the independent sets of $G$. We call these involutions flips, and use them to define a new partial order on independent sets of $G$. Trim lattices…

Combinatorics · Mathematics 2019-04-01 Hugh Thomas , Nathan Williams

We note a parallel between some ideas of stable model theory and certain topics in finite combinatorics related to the sum-product phenomenon. For a simple linear group G, we show that a finite subset X with |X X \^{-1} X |/ |X| bounded is…

Logic · Mathematics 2011-05-17 Ehud Hrushovski

Geometrical stability theory is a powerful set of model-theoretic tools that can lead to structural results on models of a simple first-order theory. Typical results offer a characterization of the groups definable in a model of the theory.…

Logic · Mathematics 2007-05-23 Steven Buechler , Olivier Lessmann

We introduce some properties describing dependence in indiscernible sequences: $F_{ind}$ and its dual $F_{Mb}$, the definable Morley property, and $n$-resolvability. Applying these properties, we establish the following results: We show…

Logic · Mathematics 2026-04-29 John Baldwin , James Freitag , Scott Mutchnik

The disjoint amalgamation property (DAP), which asserts that all spans of a class of models can be amalgamated with minimal intersection, is an important property in the context of abstract elementary classes, with connections to both…

Logic · Mathematics 2026-01-22 Jeremy Beard

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

Structural independence is the (conditional) independence that arises from the structure rather than the precise numerical values of a distribution. We develop this concept and relate it to $d$-separation and structural causal models.…

Probability · Mathematics 2025-06-24 Matthias Georg Mayer

One measure of the complexity of a first-order theory, and similarly a type, is the complexity of the formulas required to axiomatize it. We say a theory is bounded if there is an axiomatization involving only $\forall_n$-formulas for some…

Logic · Mathematics 2026-04-29 Hongyu Zhu
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