magfrump comments on Logical uncertainty, kind of. A proposal, at least. - Less Wrong

8 Post author: Manfred 13 January 2013 09:26AM

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Comment author: magfrump 15 January 2013 01:08:10AM 0 points [-]

Okay, but say the robot in ten seconds manages to prove the theorem: "For all dimensions n not equal to 4, there is exactly one smooth structure on R^n." But is unable to produce a result regarding n=4? Or more realistically, say it is able to construct 1 smooth structure on R^n for any n, and can prove that no others exist unless n=4. How does it make guesses in the case n=4?

Comment author: magfrump 15 January 2013 01:27:31AM 0 points [-]

If we want to live in the least convenient possible world assume that in second 1 it constructs the smooth structures; it takes three seconds to prove that there are no more for n>5, three seconds to prove no more for n=1,2, and three more seconds to prove there are no more for n=3 and runs out of time. These results are obtained incidentally from inequalities that arise when pursuing a proof for n=4, which is the central value of some equation at the core of the proofs. (so the proofs really say "if another smooth structure exists, it exists for n<5, 2<n<5, 3<n<5.")

Comment author: Manfred 15 January 2013 09:35:43AM *  0 points [-]

If it really can't prove any theorems that directly include the translation of "the number of smooth structures for n=4 is," it simply won't ever update that.

Comment author: magfrump 15 January 2013 07:21:16PM 0 points [-]

Well it can prove "the number of structures for n=4 is at least 1."