Timeline for Set theories that do require the existence of urelements?
Current License: CC BY-SA 3.0
4 events
| when toggle format | what | by | license | comment | |
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| Sep 22, 2016 at 19:05 | history | edited | user1448 | CC BY-SA 3.0 |
"NFU" -> "NFU+Choice"
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| Mar 4, 2011 at 20:35 | comment | added | user1448 | Fair enough; I should more accurately say NFU+Choice. NF itself is inconsistent with choice, which is essentially why NFU was devised. You're right that NF is inconsistent iff NFU can prove the existence of atoms without invoking the axiom of choice. | |
| Mar 3, 2011 at 16:00 | comment | added | Emil Jeřábek | Something's wrong. NF extends NFU and proves there are no urelements, hence you are effectively claiming that NF is inconsistent, which is actually a major open problem. | |
| Mar 3, 2011 at 15:52 | history | answered | user1448 | CC BY-SA 2.5 |