Quick way to get the repelling fixed point from the attracting fixed point?
#1
So, this may seem like an odd question, but can anyone describe for me the function that takes the attracting fixed point to the repelling fixed point? I currently have a subpar manner of calculating this, and I'm wondering if there is a quicker way.

Now, to explain, let \(|\log(y)| < 1\), so for example \(y=2\). I want a function \(f\) such that \(f(2) = 4\), and similarly for the other fixed point pairs.

That is:

\[
f(y)^{1/f(y)} = y^{1/y}\\
\]

or more specifically: \(\log(f(y))/f(y) = \log(y)/y\) for the principal branch of the log.

While \(|\log(y) | < 1\) and \(|\log f(y) | > 1\)?

I feel there must be some literature on this function. So far, I've been running the protocol:

\[
f(y) = \lim_{n\to\infty} \log^{\circ n}_{y^{1/y}}(e)\\
\]

Which works pretty well, but I'm not even sure works in the general sense. Is \(e\) always in the attracting orbit of \(\log_{y^{1/y}}(z)\) of the repelling fixed point \(f(y)\)? I feel like there may be counter examples, but I'm too lazy, and my code seems to be working Rolleyes

This problems been annoying me. And it's either something gnawingly stupid that I missed, or it's a rather deep problem.

To reiterate the question. I'm looking for a function:

\[
\begin{align}
f : \{y \in \mathbb{C}\,|\,|\log(y)| < 1\} &\to \{ y \in \mathbb{C}\,|\, |\log(y)| > 1\}\\
f(y)^{1/f(y)} &= y^{1/y}\\
\end{align}
\]

I might ask this on MO, but god knows they're all a bunch of c**** there.

Regards, James

EDIT:

here's the MO question link https://mathoverflow.net/questions/42615...attracting

I'm expecting a bunch of c***** to discredit my question by tomorrow. I hate MO.
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Messages In This Thread
Quick way to get the repelling fixed point from the attracting fixed point? - by JmsNxn - 07/06/2022, 09:40 PM

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