Timeline for Seeking clarification of ultrapower nonstandard model of arithmetic
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 31, 2023 at 2:10 | vote | accept | Dave Pritchard | ||
| Dec 31, 2023 at 2:10 | history | edited | Dave Pritchard | CC BY-SA 4.0 |
Corrections to misleading stuff in question, as proposed by responder
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| Dec 27, 2023 at 21:37 | answer | added | Dave Pritchard | timeline score: 3 | |
| Dec 27, 2023 at 16:16 | comment | added | Alex Kruckman | @JamesHanson Actually, $c$ has to be (equivalent to) the all $1$s sequence, since either $a=1$ and $b=0$ or the reverse (depending on the ultrafilter). | |
| Dec 27, 2023 at 9:28 | comment | added | Mikhail Katz | "take a quotent that gives the ultrapower: identify sequences when they agree except on finitely many components" : this is an incorrect description of the ultrapower. One has to identify sequences if they agree on a dominant set there dominant does not have to be cofinite. You are confusing ultrafilters and Frechet filters. | |
| Dec 27, 2023 at 8:23 | comment | added | James E Hanson | The $c$ is going to depend on the particular ultrafilter. Either the all $0$'s sequence or the all $1$'s sequence will work. | |
| Dec 27, 2023 at 7:37 | history | asked | Dave Pritchard | CC BY-SA 4.0 |