English

Big Ramsey degrees in universal inverse limit structures

Combinatorics 2022-05-20 v2

Abstract

We build a collection of topological Ramsey spaces of trees giving rise to universal inverse limit structures,extending Zheng's work for the profinite graph to the setting of Fra\"{\i}ss\'{e} classes of finite ordered binary relational structures with the Ramsey property. This work is based on the Halpern-L\"{a}uchli theorem, but different from the Milliken space of strong subtrees. Based on these topological Ramsey spaces and the work of Huber-Geschke-Kojman on inverse limits of finite ordered graphs, we prove that for each such Fra\"{\i}ss\'{e} class, its universal inverse limit structure has finite big Ramsey degrees under finite Baire-measurable colorings. For such \Fraisse\ classes satisfying free amalgamation as well as finite ordered tournaments and finite partial orders with a linear extension, we characterize the exact big Ramsey degrees.

Keywords

Cite

@article{arxiv.2012.08736,
  title  = {Big Ramsey degrees in universal inverse limit structures},
  author = {Natasha Dobrinen and Kaiyun Wang},
  journal= {arXiv preprint arXiv:2012.08736},
  year   = {2022}
}

Comments

27 pages, 28 figures

R2 v1 2026-06-23T21:00:20.766Z