English

Invariant Keisler measures for omega-categorical structures

Logic 2025-08-26 v2

Abstract

A recent article of Chernikov, Hrushovski, Kruckman, Krupinski, Moconja, Pillay and Ramsey finds the first examples of simple structures with formulas which do not fork over \emptyset but are universally measure zero. In this article we give the first known simple ω\omega-categorical counterexamples. These happen to be various ω\omega-categorical Hrushovski constructions. Using a probabilistic independence theorem from Jahel and Tsankov, we show how simple ω\omega-categorical structures where the forking ideal and the universally measure zero ideal coincide must satisfy a stronger version of the independence theorem.

Keywords

Cite

@article{arxiv.2211.14628,
  title  = {Invariant Keisler measures for omega-categorical structures},
  author = {Paolo Marimon},
  journal= {arXiv preprint arXiv:2211.14628},
  year   = {2025}
}

Comments

14 pages, no figures