Conformal map from Mandelbrot set to Disk

613 Views Asked by At

Conformal maps from the complement of the Mandelbrot set to the disk are well known. Also, it is known that there exists a surjective conformal map from the interior of the Mandelbrot set to the disk by the Riemann mapping theorem.

Is an explicit example of a conformal map from the Mandelbrot set to the unit disk known?

1

There are 1 best solutions below

2
On BEST ANSWER

For the revised question suggested in the comment:

you should be able to do it piecewise on the connected components of the interior

You can use the derivative of the limit cycle of points in hyperbolic components as a coordinate in the unit disc. I believe the mapping is conformal, but I don't have a proof handy...

interior coordinates

Practically, you would check candidate periods $p$ where $|z_p|$ reaches a new minimum in iterations of $z_{n + 1} = f_c(z_n)$. Use Newton's method to solve $z = f_c^p(z)$, using $z_p$ as initial guess. If $\left|\frac{\partial}{\partial z} f_c^p(z)\right| \le 1$ (evaluated at the root you found), then $c$ is inside a hyperbolic component of period $p$, and $w = \frac{\partial}{\partial z} f_c^p(z)$ is mapped to the unit disc. I have no proof of correctness of this algorithm, but it seems to work...