Definable $(\omega, 2)$-theorem for families with VC-codensity less than $2$
Logic
2025-04-29 v3 Combinatorics
Abstract
Let be a family of sets with VC-codensity less than . We prove that, if has the -property (for any infinitely many sets in , at least among them intersect), then can be partitioned into finitely many subfamilies, each with the finite intersection property. If is definable in some first-order structure, then these subfamilies can be chosen definable too. This is a strengthening of the case of the definable - conjecture in model theory and of the Alon-Kleitman-Matou\v{s}ek -theorem in combinatorics.
Cite
@article{arxiv.2205.13665,
title = {Definable $(\omega, 2)$-theorem for families with VC-codensity less than $2$},
author = {Pablo Andújar Guerrero},
journal= {arXiv preprint arXiv:2205.13665},
year = {2025}
}
Comments
Proof streamlined after referee comments. I have two last names: And\'ujar Guerrero. ArXiV is currently unable to represent this and considers And\'ujar a middle name (when creating the BibTeX citation etc)