Timeline for Definability in countable nonstandard models of Peano arithmetic
Current License: CC BY-SA 4.0
10 events
| when toggle format | what | by | license | comment | |
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| Feb 28, 2022 at 15:40 | answer | added | Noah Schweber | timeline score: 2 | |
| Oct 25, 2020 at 7:16 | review | Close votes | |||
| Oct 30, 2020 at 3:03 | |||||
| Oct 25, 2020 at 6:49 | history | edited | YCor |
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| Apr 23, 2020 at 20:35 | comment | added | Ali Enayat | @MarcusDubious To see that the definable elements form an elementray submodel (in the presence of definable Skolem functions), apply the so-called Tarski-Vaught test of elementarity, the test is explained on: math.stackexchange.com/questions/3226832/… | |
| Apr 23, 2020 at 20:01 | comment | added | Marcus Dubious | Why does having definable Skolem functions imply that the set of definable elements of any model is an elementary submodel? | |
| Apr 23, 2020 at 9:47 | history | edited | YCor | CC BY-SA 4.0 |
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| Apr 23, 2020 at 8:42 | review | Close votes | |||
| Apr 29, 2020 at 16:12 | |||||
| Apr 23, 2020 at 8:30 | comment | added | Emil Jeřábek | Yes. PA has definable Skolem functions, hence the set of definable elements of any model is an elementary submodel, which is nonstandard as long as the original model is not elementarily equivalent to $\mathbb N$. | |
| Apr 23, 2020 at 8:06 | review | First posts | |||
| Apr 23, 2020 at 8:23 | |||||
| Apr 23, 2020 at 7:56 | history | asked | Marcus Dubious | CC BY-SA 4.0 |