English

Topological dynamics of unordered Ramsey structures

Logic 2014-04-25 v2

Abstract

In this paper we investigate the connections between Ramsey properties of Fraisse classes K and the universal minimal flow M(G_K) of the automorphism group G_K of their Fraisse limits. As an extension of a result of Kechris, Pestov and Todorcevic we show that if the class K has finite Ramsey degree for embeddings, then this degree equals the size of M(G_K). We give a partial answer to a question of Angel, Kechris and Lyons showing that if K is a relational Ramsey class and G_K is amenable, then M(G_K) admits a unique invariant Borel probability measure that is concentrated on a unique generic orbit.

Keywords

Cite

@article{arxiv.1401.7766,
  title  = {Topological dynamics of unordered Ramsey structures},
  author = {Moritz Müller and András Pongrácz},
  journal= {arXiv preprint arXiv:1401.7766},
  year   = {2014}
}
R2 v1 2026-06-22T02:57:37.927Z