English

Infinite dimensional Ellentuck spaces and Ramsey-classification theorems

Logic 2015-09-22 v2

Abstract

We extend the hierarchy of finite-dimensional Ellentuck spaces to infinite dimensions. Using uniform barriers BB on ω\omega as the prototype structures, we construct a class of continuum many topological Ramsey spaces EB\mathcal{E}_B which are Ellentuck-like in nature, and form a linearly ordered hierarchy under projection. We prove new Ramsey-classification theorems for equivalence relations on fronts, and hence also on barriers, on the spaces EB\mathcal{E}_B, extending the Pudlak-Rodl Theorem for barriers on the Ellentuck space. The inspiration for these spaces comes from continuing the iterative construction of the forcings P([\om]k)/\Fink\mathcal{P}([\om]^k)/\Fin^{\otimes k} to the countable transfinite. The σ\sigma-closed partial order (EB,\sse\FinB)(\mathcal{E}_B, \sse^{\Fin^{B}}) is forcing equivalent to P(B)/\FinB\mathcal{P}(B)/\Fin^{B}, which forces a non-p-point ultrafilter GB\mathcal{G}_B. The present work forms the basis for further work classifying the Rudin-Keisler and Tukey structures for the hierarchy of the generic ultrafilters GB\mathcal{G}_B.

Keywords

Cite

@article{arxiv.1508.06533,
  title  = {Infinite dimensional Ellentuck spaces and Ramsey-classification theorems},
  author = {Natasha Dobrinen},
  journal= {arXiv preprint arXiv:1508.06533},
  year   = {2015}
}

Comments

36 pages, submitted, (very slightly revised exposition)

R2 v1 2026-06-22T10:42:04.537Z