Ramsey growth in some NIP structures
Abstract
We investigate bounds in Ramsey's theorem for relations definable in NIP structures. Applying model-theoretic methods to finitary combinatorics, we generalize a theorem of Bukh and Matousek [B. Bukh, J. Matou\v{s}ek. "Erd\H{o}s-Szekeres-type statements: Ramsey function and decidability in dimension ", Duke Mathematical Journal 163.12 (2014): 2243-2270] from the semialgebraic case to arbitrary polynomially bounded -minimal expansions of , and show that it doesn't hold in . This provides a new combinatorial characterization of polynomial boundedness for -minimal structures. We also prove an analog for relations definable in -minimal structures, in particular for the field of the -adics. Generalizing [D. Conlon, J. Fox, J. Pach, B. Sudakov, A. Suk "Ramsey-type results for semi-algebraic relations", Transactions of the American Mathematical Society 366.9 (2014): 5043-5065], we show that in distal structures the upper bound for -ary definable relations is given by the exponential tower of height .
Cite
@article{arxiv.1609.05951,
title = {Ramsey growth in some NIP structures},
author = {Artem Chernikov and Sergei Starchenko and Margaret E. M. Thomas},
journal= {arXiv preprint arXiv:1609.05951},
year = {2021}
}
Comments
v.3 26 pages; Section 5 was expanded, providing a discussion of polynomial boundedness in this setting and generalizing the proof to demonstrate that the result applies to P-minimal expansions of fields including analytic expansions and finite extensions of Q_p; minor corrections and presentation improvements were made throughout the article