Imaginary iterates of exponentiation
#10
I always like to relate things to the unit disk when doing these iterations.

The value \(\exp^{\circ it}(z)\) traces an almost elliptic path, similar to \(\lambda^it\) for \(\lambda\) the multiplier. Essentially the object looks very much like \(z \mapsto \lambda^i z\), but it's placed in this weird fractally shape (the immediate basin). If you map the immediate basin (using Schroder) to \(\mathbb{C}\), this comparison becomes directly evident. Fun fact, you can use this to prove that the immediate basin about the fixed point is simply connected. There exists a sequence of jordan curves which slowly approximate the boundary.

\[
\lim_{x\to\partial \mathcal{A}} \exp^{\circ it}(x)\\
\]

You can prove this is a jordan curve with some work, but it's doable. So picture a bunch of almost elipses which start to slowly get more and more fractally as \(x\) approaches the boundary, and more and more circular as x approaches the fixed point.

You can copy paste a lot from the mapping \(z \mapsto \lambda^i z\), thanks to the Schroder function. All in all, it's not something inherently that interesting though. The function \(\exp^{\circ it}(z)\) is definitely more interesting--especially for periodic, about the fixed point, solutions. Looking at the boundary of the immediate basin, you would never guess that it is a Jordan curve, and that the immediate basin is simply connected, but it is. Totally weird looking fractally shape that it is. This limit sort of lets you watch as a nice looking ellipse starts to look more and more fractally.
Reply


Messages In This Thread
Imaginary iterates of exponentiation - by jaydfox - 09/12/2007, 07:13 AM
RE: Imaginary iterates of exponentiation - by JmsNxn - 07/01/2022, 09:09 PM

Possibly Related Threads…
Thread Author Replies Views Last Post
  [GEN DYN] Iterates of tanh(A x)^(2m+1) tommy1729 0 2,652 05/22/2023, 10:23 PM
Last Post: tommy1729
  Has anyone studied the iterates of \(\frac{1}{e^{-1/z}}\) Daniel 2 3,414 05/22/2023, 08:56 PM
Last Post: tommy1729
  Discussing fractional iterates of \(f(z) = e^z-1\) JmsNxn 2 4,873 11/22/2022, 03:52 AM
Last Post: JmsNxn
Question Convergent Complex Tetration Bases With the Most and Least Imaginary Parts Catullus 0 2,862 07/10/2022, 06:22 AM
Last Post: Catullus
  Merged fixpoints of 2 iterates ? Asymptotic ? [2019] tommy1729 1 8,153 09/10/2019, 11:28 AM
Last Post: sheldonison
  Half-iterates and periodic stuff , my mod method [2019] tommy1729 0 5,218 09/09/2019, 10:55 PM
Last Post: tommy1729
  Approximation to half-iterate by high indexed natural iterates (base on ShlThrb) Gottfried 1 7,699 09/09/2019, 10:50 PM
Last Post: tommy1729
  half-iterates of x^2-x+1 Balarka Sen 2 12,320 04/30/2013, 01:14 AM
Last Post: tommy1729
  Q: Exponentiation of a carleman-matrix Gottfried 0 6,916 11/19/2012, 10:18 AM
Last Post: Gottfried
  The imaginary tetration unit? ssroot of -1 JmsNxn 2 13,556 07/15/2011, 05:12 PM
Last Post: JmsNxn



Users browsing this thread: 1 Guest(s)