Timeline for A question about Universal sets.
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 20 at 16:43 | answer | added | Zuhair Al-Johar | timeline score: 0 | |
| Feb 23, 2013 at 20:44 | vote | accept | Garabed Gulbenkian | ||
| Feb 22, 2013 at 23:09 | comment | added | Asaf Karagila♦ | It should be remarked that while NF has a universal set, $U$ and its subsets are indeed elements of $U$; one still have a notion of proper classes in NF. For example the Russell class of all sets which do not contain themselves cannot be a set, and indeed in NF it is not. But it is still a collection and we can still say meaningful things about the members of this collection (as we do with every non-empty collection). | |
| Feb 22, 2013 at 22:40 | answer | added | Joel David Hamkins | timeline score: 7 | |
| Feb 22, 2013 at 20:14 | answer | added | Noah Schweber | timeline score: 8 | |
| Feb 22, 2013 at 19:55 | history | asked | Garabed Gulbenkian | CC BY-SA 3.0 |