Timeline for Can iterating countable unions give every set? (ZF)
Current License: CC BY-SA 2.5
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| Jul 27, 2010 at 0:19 | vote | accept | CommunityBot | ||
| Jul 27, 2010 at 0:19 | |||||
| Jul 24, 2010 at 2:01 | comment | added | Daniel Mehkeri | Okay, so how about the converse? Given such a set S, can we find an ordinal with uncountable cofinality? Perhaps just take its rank? If that is correct, then, combining that with François' answer, I would conclude the answer to the original question is «no», ZF cannot prove the existence of such an S. | |
| Jul 23, 2010 at 18:18 | history | edited | Joel David Hamkins | CC BY-SA 2.5 |
added 561 characters in body
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| Jul 23, 2010 at 11:44 | history | answered | Joel David Hamkins | CC BY-SA 2.5 |