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Apr 13, 2017 at 12:57 history edited CommunityBot
replaced http://mathoverflow.net/ with https://mathoverflow.net/
Apr 19, 2014 at 18:43 comment added Peter LeFanu Lumsdaine @ChristianRemling: “The truth of a conjecture can’t make a set $\Pi^0_1$ if it wasn't so to start with.” Sure, but the $\Pi^0_1$-ness of a set can be implied by (or even equivalent to) some conjecture. A proof of the conjecture can’t change whether the set is $\Pi^0_1$, but it can tell us whether or not it is.
Apr 18, 2014 at 15:47 history bounty ended John Sidles
Apr 18, 2014 at 0:44 history made wiki Post Made Community Wiki by Todd Trimble
Apr 18, 2014 at 0:24 comment added John Sidles Alex Gavrilov, you have received the bounty. Thank you for taking the time to give such a well-considered answer.
Apr 17, 2014 at 23:07 vote accept John Sidles
Apr 11, 2014 at 20:48 comment added Bjørn Kjos-Hanssen Once it's proven, the sentence is proven to be equivalent to a $\Pi^0_1$ statement, namely $0=0$. When we speak of "a sentence" we probably mean "up to provable equivalence" since the Millennium Problems are only defined up to provable equivalence...
Apr 11, 2014 at 19:10 comment added Monroe Eskew I don't see how assuming a statement to be true makes it $\Pi^0_1$.
Apr 11, 2014 at 17:58 comment added Alex Gavrilov Yes, but I mean it is proven and assumed to be true.
Apr 11, 2014 at 17:54 comment added Monroe Eskew What do you mean by, "After all, once a conjecture is proven, it is in $\Pi^0_1$ by definition"? Logically speaking, a sentence $\sigma$ is not in general equivalent to "there is a proof of $\sigma$," as Goedel shows.
Apr 11, 2014 at 17:35 history answered Alex Gavrilov CC BY-SA 3.0