Timeline for Injection into a proper class and choice without regularity
Current License: CC BY-SA 4.0
5 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 26, 2019 at 10:32 | vote | accept | Holo | ||
| Apr 26, 2019 at 10:32 | comment | added | Holo | Oh, each atom as an omega sequence of ordinals, I understand now, thanks! | |
| Apr 26, 2019 at 10:01 | comment | added | Asaf Karagila♦ | Well, map the atom indexed by the constant sequence $\alpha$ to $\alpha$. Of course, you need to show that this map is stable under permutations, which it is, if you extend it "correctly" (i.e. close this class function under permutations to determine its actual domain). | |
| Apr 26, 2019 at 9:59 | comment | added | Holo | Hi Asaf, thanks for answering, you wrote "the atoms are indexed by countable sequences of ordinals, so that there are always surjections onto every set but there is no omega sequence", how does the first and second part works together? And how does it gives you surjective onto a set like omega2? | |
| Apr 25, 2019 at 23:20 | history | answered | Asaf Karagila♦ | CC BY-SA 4.0 |