Timeline for Are countable models constructible?
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Feb 26, 2022 at 1:56 | vote | accept | Frode Alfson Bjørdal | ||
| Feb 25, 2022 at 16:49 | comment | added | Frode Alfson Bjørdal | Ah, yes of course! :) What if (as is my real interest) S is ZFC minus the power set axiom, plus, for a countable ordinal $\gamma$, less than $\gamma$ applications of the power set operation? | |
| Feb 24, 2022 at 16:32 | comment | added | Andreas Blass | Yes, $V\neq L$ is an axiom not in ZFC. But (1) is only part of ZFC. So the combination is not an extension of ZFC. | |
| Feb 24, 2022 at 15:37 | comment | added | Frode Alfson Bjørdal | I don't understand. Doesn't (2) invoke an extra axiom? – | |
| Feb 24, 2022 at 15:02 | comment | added | Andreas Blass | @FAB The $S$ in the first paragraph of my answer does not extend ZFC. | |
| Feb 24, 2022 at 14:54 | comment | added | Frode Alfson Bjørdal | What about any first order S which does not extend ZFC? Will such an S have a model $L_\alpha$ for countable $\alpha$ if it has a countable model? | |
| Feb 24, 2022 at 1:22 | history | answered | Andreas Blass | CC BY-SA 4.0 |