7:22 AM
These topics are not my strong suit. (In fact, I prefer to avoid methamatematics.) But I thought it is worth mentioning, just in case somebody else is interested in the discussion there.)
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I heard that the P vs NP question is equivalent to a $\Pi_2^0$ sentence, and that the Riemann hypothesis is equivalent to a $\Pi_1^0$ sentence. Many known mathematical theorems state that some specific $\Pi_2^0$ sentence is actually true, take Goodstein's theorem for example. The related Paris-Ha...
2 hours later…
9:15 AM
1 hour later…
10:29 AM
in Mathematics, 10 secs ago, by Martin Sleziak
@LeakyNun I have seen logarithms of cardinals. But I have not encountered logarithms of ordinals.
1 hour later…
11:51 AM
in Mathematics, 3 mins ago, by Martin Sleziak
@LeakyNun Maybe Cantor normal form could give you something like logarithm with the base $\omega$? I am not sure. (I did not encounter situation where such things would be needed.)
in Mathematics, 35 secs ago, by Martin Sleziak
@LeakyNun I simply tried to search in Google Books and I found this in Enderton's Set Theory.
in Mathematics, 40 secs ago, by Martin Sleziak
Logarithm Theorem. Assume that $\alpha$ and $\beta$ are ordinal numbers with $\alpha\ne0$ and $\beta$ (the base) greater than $1$. Then there are unique ordinal numbers $\gamma$, $\delta$ nad $\rho$ (the logarithm, the coefficient, and the remainder) such that $$\alpha=\beta^\gamma\cdot\delta+\rho \land 0\ne\delta\in\beta \land \rho\in\beta^\gamma$$
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