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Aug 7, 2016 at 11:46 comment added Payam Seraji You are wellcome.
Aug 7, 2016 at 7:55 comment added Erfan Khaniki @PayamSeraji: Interesting comment. Thank you.
Aug 6, 2016 at 20:00 comment added Payam Seraji For all levels of the arithmetical hierarchy ($\Sigma_n$, $\Pi_n$, $\Delta_n$), a definable set $A$ my be (for example) "$\Sigma_n$ in the standard model of arithetic" or "provabily $\Sigma_n$ in $T$). Obviously the later implies the former (if $T$ is sound) but the converse is not necessarily true. So I think another name for your concept is "provabily (in $T$) $\Delta_1$".
Aug 6, 2016 at 0:46 comment added Erfan Khaniki @NoahSchweber:I mean $T$ is in language of arithmetic($\mathcal{L}_T=\{0,S,+,\cdot\}$)
Aug 6, 2016 at 0:26 comment added Noah Schweber What does "arithmetical" mean here? (Since $T$ is recursively enumerable, it's certainly arithmetical in the computability-theoretic sense . . .)
Aug 5, 2016 at 18:12 history edited Erfan Khaniki CC BY-SA 3.0
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Aug 5, 2016 at 18:11 comment added Erfan Khaniki @JoelDavidHamkins: I edited my post. about your third question, Is there any difference for definition of provably decidable set if for example $I\Delta_0\subseteq T$ ?
Aug 5, 2016 at 18:05 history edited Erfan Khaniki CC BY-SA 3.0
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Aug 5, 2016 at 17:31 comment added Joel David Hamkins Could you clarify whether you intend to assume that $T$ is computably enumerable? Or that $T$ is true in the standard model? Or that $T$ contains some specific weak theory?
Aug 5, 2016 at 17:13 history asked Erfan Khaniki CC BY-SA 3.0