Timeline for Set theory without the empty set
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 31, 2022 at 13:18 | answer | added | Flash Sheridan | timeline score: 4 | |
| May 30, 2022 at 20:27 | comment | added | Burak | I think it depends on what you mean by a "set theory". There is one such theory that has been explored for over 100 years in disguise: Take the usual axioms of ZFC and flip the $\in$ symbol in all instances. Then you get a "set theory". It proves the same theorems as ZFC with $\in$ flipped. Therefore this theory does not prove that there is an empty set. The "sets" here do not align with our intuition of a "set" though: For example, given sets x,y, there is a set z which is contained in both x and y, but nothing else. (I couldn't help but post this "troll" answer, sorry :) | |
| May 28, 2022 at 22:28 | history | became hot network question | |||
| May 28, 2022 at 17:05 | comment | added | Alec Rhea | Any reason for the downvote? | |
| May 28, 2022 at 16:40 | vote | accept | Alec Rhea | ||
| May 28, 2022 at 14:38 | answer | added | Philip Ehrlich | timeline score: 23 | |
| May 28, 2022 at 14:22 | history | asked | Alec Rhea | CC BY-SA 4.0 |