Questions tagged [complex-dynamics]

This tag is for questions relating to complex dynamics, study of dynamical systems defined by iteration of functions on complex number spaces. It was an area of research established by Fatou and Julia towards the beginning of the last century.

Complex dynamics concerns the iteration of analytic functions of one complex variable. Such iteration arises, for example, when solving complex equations by Newton’s method. For each function, the complex plane is divided into two fundamentally different parts – the Fatou set, where the behavior of the iterates is stable under local variation, and the Julia set, where it is chaotic. The subject of complex dynamics experienced a huge resurgence of interest in the 1980s, with the advent of computer graphics illustrating the highly intricate nature of most Julia sets, and the introduction of powerful new techniques from complex analysis leading to much profound new work.

References:

https://en.wikipedia.org/wiki/Complex_dynamics

369 questions
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Complex dynamics: iterates of rational function : Julia and fatou set

Prove that attracting fixed points of rational map lies in fatou set and repelling fixed point of rational map lies in the julia set
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Preimage of circle with critical point and its image inside is simple and closed

I am reading Devaney's "An Introduction to Chaotic Dynamical Systems" and I am trying to convince myself of a claim made there (Section 3.6, proposition 6.2). The proposition concerns showing that the Julia set of $f(z)=z^2+c$ is simple and closed…
user30523
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bounds on size of Julia sets inside Mandelbrot set

Let $J_c$ be the Julia set for the quadratic polynomial $f_c(z) = z^2 + c$, and the Mandelbrot set is $M = \{ c \in \mathbb{C} : J_c \text{ is connected} \}$. Call the closed disc of radius $2$ centered at the origin $D = \{ c \in \mathbb{C} : |c|…
Claude
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Mandelbrot set - Magnitude Decreasing Method (MDM/M)

Consider the following picture: I made this this image the following way: While computing $z_{n+1} = z_n^2 + c$ with $z_0 = 0$ and $c$ being the point on the complex plane, check if $|z_{n+1}| < |z_n|$. If so, increase a counter $D$. Repeat until…
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Filled Julia set

How would I find the filled Julia set for $f(z)=z^3$? I know it should be the filled unit circle, but I don't quite understand the math. This is what I have so far: Fixed points $z^3=z$ so…
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How can I get this estimation?

This question is from the book Complex Dynamics by Gamelin, the theorem 2.1 's proof. Suppose $0$ is an attracting fixed point of $f$, with multiplier $\lambda$ satisfying $0<|\lambda|<1$ . How can I get that: for $\delta$ small, there exists $C>0$,…
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Polynomials of a particular form

I have an iterative polynomial in fractal geometry, namely $Z = Z^2 + C$. What is the name of the polynomial of the more general form $Z = Z^\beta + Z^\gamma + ... + C$? I am calling them Julia-Fatou-Mandelbrot polynomials. Is that incorrect?
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Boundary of basin of attraction of $\infty$ = closure of repelling periodic points.

I have met five different definitions of the Julia set and I am trying to work out why they are equivalent. I haven't managed to find a reference showing why two of these are equivalent. Why is the boundary of the basin of attraction of $\infty$…
user30523
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polynomial conjugate

It is well known that any quadratic polynomial is conjugated to a polynomial of the form $z^2+c$. How about polynomials with higher degree, such as $z^n+a_1z^{n-1}+\cdots+a_{n-1}$, is it also conjugated to a polynomial of the form $z^n+c$.
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