Timeline for Show that Z2 is not conservative over PA
Current License: CC BY-SA 3.0
13 events
when toggle format | what | by | license | comment | |
---|---|---|---|---|---|
Apr 13, 2017 at 12:58 | history | edited | CommunityBot |
replaced http://mathoverflow.net/ with https://mathoverflow.net/
|
|
Jan 26, 2014 at 4:12 | comment | added | François G. Dorais | @NikWeaver: Yes, I'm aware of your disagreement and I agree with you that "predicative" is almost systematically misused. I tend to agree with your objection regarding $\Sigma^1_1$ induction. It's also unfair to call $\mathsf{ATR}_0$ predicative since it fits the Friedman-Simpson predicative reductionist philosophy rather than the actual predicative philosophy. | |
Jan 26, 2014 at 3:48 | comment | added | Nik Weaver | @François: I firmly disagree that either $ATR_0$ or $ACA_0 + I\Sigma^1_1$ is predicative. | |
Jan 26, 2014 at 3:20 | history | edited | A.C. | CC BY-SA 3.0 |
added 1079 characters in body
|
Jan 26, 2014 at 3:00 | vote | accept | A.C. | ||
Jan 26, 2014 at 1:40 | comment | added | A.C. | Yikes! My apologies; I'm new to reverse mathematics. Should I edit the question to remove the offending word or will that create more confusion than it resolves? | |
Jan 26, 2014 at 1:25 | comment | added | François G. Dorais | I think the confusion is the concern with "impredicativity." The reason why $\mathsf{ATR}_0$ and $\mathsf{ACA}_0+\mathsf{I}\Sigma^1_1$ were brought up is that these are predicative systems. | |
Jan 26, 2014 at 1:11 | history | edited | A.C. | CC BY-SA 3.0 |
added 966 characters in body
|
Jan 25, 2014 at 22:00 | answer | added | François G. Dorais | timeline score: 7 | |
Jan 25, 2014 at 21:58 | review | First posts | |||
Jan 25, 2014 at 22:00 | |||||
Jan 25, 2014 at 21:57 | answer | added | Carl Mummert | timeline score: 5 | |
Jan 25, 2014 at 21:54 | answer | added | Noah Schweber | timeline score: 4 | |
Jan 25, 2014 at 21:42 | history | asked | A.C. | CC BY-SA 3.0 |