Timeline for Question about undecidable consequences of Con, learnability and arithmetical complexity of logical consequence
Current License: CC BY-SA 3.0
7 events
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| Apr 13, 2017 at 12:58 | history | edited | CommunityBot |
replaced http://mathoverflow.net/ with https://mathoverflow.net/
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| Jun 6, 2013 at 11:33 | vote | accept | mtg | ||
| Jun 6, 2013 at 10:27 | answer | added | Marek Czarnecki | timeline score: 3 | |
| Jun 6, 2013 at 0:15 | comment | added | mtg | Thanks. You're right, but let's look at the theory I mentioned: PA+(Set of true Pi_1-sentences) which closed under consequence gives us nonlearnable theory. I don't "see", how - having a computable reduction of Set of true Pi_1-sentences to the set T- we obtain theories with different complexities? | |
| Jun 5, 2013 at 23:48 | comment | added | Dan Turetsky | I don't see any mistakes. A good chunk of the complexity of T comes from excluding certain sentences; specifically, those sentences provable in PA. But adding PA and then closing under consequence restores those sentences. That's why the complexity decreases. | |
| Jun 5, 2013 at 22:52 | history | edited | mtg |
added a tag
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| Jun 5, 2013 at 21:54 | history | asked | mtg | CC BY-SA 3.0 |