Topological Ramsey spaces of equivalence relations and a dual Ramsey theorem for countable ordinals
We define a collection of topological Ramsey spaces consisting of equivalence relations on \(\omega\) with the property that the minimal representatives of the equivalence classes alternate according to a fixed partition of \(\omega\). To prove the associated pigeonhole principles, we make use of th...
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Veröffentlicht in: | arXiv.org 2021-12 |
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Hauptverfasser: | , |
Format: | Artikel |
Sprache: | eng |
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Online-Zugang: | Volltext |
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Zusammenfassung: | We define a collection of topological Ramsey spaces consisting of equivalence relations on \(\omega\) with the property that the minimal representatives of the equivalence classes alternate according to a fixed partition of \(\omega\). To prove the associated pigeonhole principles, we make use of the left-variable Hales-Jewett theorem and its extension to an infinite alphabet. We also show how to transfer the corresponding infinite-dimensional Ramsey results to equivalence relations on countable limit ordinals (up to a necessary restriction on the set of minimal representatives of the equivalence classes) in order to obtain a dual Ramsey theorem for such ordinals. |
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ISSN: | 2331-8422 |