Talk:Borel determinacy theorem
 | This article is rated B-class on Wikipedia's content assessment scale. It is of interest to the following WikiProjects: | ||||||||||
| |||||||||||
Comments
[edit]Friedman's theorem
[edit]"Friedman's theorem of 1971 showed that there is no countable ordinal δ such that Vδ satisfies Borel determinacy."
This doesn't seem right; isn't Borel determinacy a statement about the existence or nonexistence of sets living in Vω+ω, so that if you start with a model of ZFC then Vδ will satisfy Borel determinacy for any δ≥ω+ω? I looked up Friedman's theorem, and it seems that what he actually does is construct a different model Lω+ω, related to the constructible universe, which satisfies Z but not Borel determinacy.
Michael Shulman (talk) 21:06, 8 March 2008 (UTC)
Done Correct, the statement in the article has since been fixed. AxelBoldt (talk) 16:36, 28 January 2022 (UTC)