Borel Determinacy and Metamathematics
Borel determinacy states that if G(T;X) is a game and X is Borel, then G(T;X) is determined. Proved by Martin in 1975, Borel determinacy is a theorem of ZFC set theory, and is, in fact, the best determinacy result in ZFC. However, the proof uses sets of high set theoretic type (N1 many power sets of...
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2001
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ndltd-unt.edu-info-ark-67531-metadc30612017-03-17T08:35:50Z Borel Determinacy and Metamathematics Bryant, Ross Descriptive set theory. Metamathematics. Borel Determinacy Descriptive Set Theory Logic Foundations Borel determinacy states that if G(T;X) is a game and X is Borel, then G(T;X) is determined. Proved by Martin in 1975, Borel determinacy is a theorem of ZFC set theory, and is, in fact, the best determinacy result in ZFC. However, the proof uses sets of high set theoretic type (N1 many power sets of ω). Friedman proved in 1971 that these sets are necessary by showing that the Axiom of Replacement is necessary for any proof of Borel Determinacy. To prove this, Friedman produces a model of ZC and a Borel set of Turing degrees that neither contains nor omits a cone; so by another theorem of Martin, Borel Determinacy is not a theorem of ZC. This paper contains three main sections: Martin's proof of Borel Determinacy; a simpler example of Friedman's result, namely, (in ZFC) a coanalytic set of Turing degrees that neither contains nor omits a cone; and finally, the Friedman result. University of North Texas Jackson, Stephen C. Brand, Neal 2001-12 Thesis or Dissertation Text oclc: 51977978 https://digital.library.unt.edu/ark:/67531/metadc3061/ ark: ark:/67531/metadc3061 English Public Copyright Bryant, Ross David Copyright is held by the author, unless otherwise noted. All rights reserved. |
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English |
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Descriptive set theory. Metamathematics. Borel Determinacy Descriptive Set Theory Logic Foundations |
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Descriptive set theory. Metamathematics. Borel Determinacy Descriptive Set Theory Logic Foundations Bryant, Ross Borel Determinacy and Metamathematics |
description |
Borel determinacy states that if G(T;X) is a game and X is Borel, then G(T;X) is determined. Proved by Martin in 1975, Borel determinacy is a theorem of ZFC set theory, and is, in fact, the best determinacy result in ZFC. However, the proof uses sets of high set theoretic type (N1 many power sets of ω). Friedman proved in 1971 that these sets are necessary by showing that the Axiom of Replacement is necessary for any proof of Borel Determinacy. To prove this, Friedman produces a model of ZC and a Borel set of Turing degrees that neither contains nor omits a cone; so by another theorem of Martin, Borel Determinacy is not a theorem of ZC. This paper contains three main sections: Martin's proof of Borel Determinacy; a simpler example of Friedman's result, namely, (in ZFC) a coanalytic set of Turing degrees that neither contains nor omits a cone; and finally, the Friedman result. |
author2 |
Jackson, Stephen C. |
author_facet |
Jackson, Stephen C. Bryant, Ross |
author |
Bryant, Ross |
author_sort |
Bryant, Ross |
title |
Borel Determinacy and Metamathematics |
title_short |
Borel Determinacy and Metamathematics |
title_full |
Borel Determinacy and Metamathematics |
title_fullStr |
Borel Determinacy and Metamathematics |
title_full_unstemmed |
Borel Determinacy and Metamathematics |
title_sort |
borel determinacy and metamathematics |
publisher |
University of North Texas |
publishDate |
2001 |
url |
https://digital.library.unt.edu/ark:/67531/metadc3061/ |
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AT bryantross boreldeterminacyandmetamathematics |
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