Timeline for Natural $\Pi^1_2$ (or worse) classes of structures?
Current License: CC BY-SA 3.0
10 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jan 6, 2015 at 21:54 | vote | accept | Noah Schweber | ||
| Oct 28, 2013 at 17:45 | answer | added | Henry Towsner | timeline score: 7 | |
| Oct 27, 2013 at 8:30 | comment | added | Asaf Karagila♦ | @Mariano: While I agree with your and Noah about this not necessarily being a good idea, there's an excellent reason for this notation and the relations between are excellent. That aside, you can see the boldface notation sometimes written as a lightface+under-tilde. This, I was told, is a result of "standard" boldface notation when writing on blackboards. Some papers I ran into used that notation instead. Amusingly, the same can be said about names in forcing, which were written as boldface letters, and then as under-tilded letters (as they are written today by some authors, e.g. Shelah). | |
| Oct 27, 2013 at 8:04 | comment | added | Noah Schweber | I tend to agree. It's standardized, unfortunately. | |
| Oct 27, 2013 at 7:50 | comment | added | Mariano Suárez-Álvarez | I wonder about the goodness of the idea of using font weight (of Greek letters!) as an apparently significative notation in this case! | |
| Oct 27, 2013 at 7:04 | history | edited | Noah Schweber | CC BY-SA 3.0 |
added 142 characters in body
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| Oct 27, 2013 at 1:04 | comment | added | Noah Schweber | I don't think so; e.g., the set of reals coding well-orderings is lightface $\Pi^1_1$. | |
| Oct 27, 2013 at 1:00 | answer | added | Ulrik Buchholtz | timeline score: 7 | |
| Oct 27, 2013 at 0:45 | comment | added | Asaf Karagila♦ | I suppose that all of these are boldface $\mathbf\Pi^1_n$, right? | |
| Oct 27, 2013 at 0:17 | history | asked | Noah Schweber | CC BY-SA 3.0 |