Intersecting sets in probability spaces and Shelah's classification

Fuente: arXiv
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Autores principales: Chernikov, Artem, Towsner, Henry
Formato: Preprint
Publicado: 2024
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author Chernikov, Artem
Towsner, Henry
author_facet Chernikov, Artem
Towsner, Henry
contents For $n \in \mathbb{N}$ and $\varepsilon > 0$, given a sufficiently long sequence of events in a probability space all of measure at least $\varepsilon$, some $n$ of them will have a common intersection. A more subtle pattern: for any $0 < p < q < 1$, we cannot find events $A_i$ and $B_i$ so that $μ\left( A_i \cap B_j \right) \leq p$ and $μ\left( A_j \cap B_i\right) \geq q$ for all $1 < i < j < n$, assuming $n$ is sufficiently large. This is closely connected to model-theoretic stability of probability algebras. We survey some results from our recent work on more complicated patterns that arise when our events are indexed by multiple indices. In particular, how such results are connected to higher arity generalizations of de Finetti's theorem in probability, structural Ramsey theory, hypergraph regularity in combinatorics, and model theory.
format Preprint
id arxiv_https___arxiv_org_abs_2406_18772
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Intersecting sets in probability spaces and Shelah's classification
Chernikov, Artem
Towsner, Henry
Combinatorics
Logic
Probability
05C55, 60G09, 62E10, 03C45
For $n \in \mathbb{N}$ and $\varepsilon > 0$, given a sufficiently long sequence of events in a probability space all of measure at least $\varepsilon$, some $n$ of them will have a common intersection. A more subtle pattern: for any $0 < p < q < 1$, we cannot find events $A_i$ and $B_i$ so that $μ\left( A_i \cap B_j \right) \leq p$ and $μ\left( A_j \cap B_i\right) \geq q$ for all $1 < i < j < n$, assuming $n$ is sufficiently large. This is closely connected to model-theoretic stability of probability algebras. We survey some results from our recent work on more complicated patterns that arise when our events are indexed by multiple indices. In particular, how such results are connected to higher arity generalizations of de Finetti's theorem in probability, structural Ramsey theory, hypergraph regularity in combinatorics, and model theory.
title Intersecting sets in probability spaces and Shelah's classification
topic Combinatorics
Logic
Probability
05C55, 60G09, 62E10, 03C45
url https://arxiv.org/abs/2406.18772