Questions tagged [julia-set]

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Transformation of Julia set sequence emerging from meromorphic function

I consider a sequence of meromorphic functions on the Riemann sphere $f_k:\hat{\mathbb{C}} \to \hat{\mathbb{C}}$ for $k\in\mathbb{N}$ of the form $$f_k(z)=\sum_{j=1}^{n_k}\dfrac{1}{(z-p_j)^{c_j}}$$ ...
Jens Fischer's user avatar
1 vote
1 answer
101 views

Dense orbits for a rational map

Given a complex rational function $f$ and $z\in \mathbb C$, let $O^+(z)=\{f^n(z):n\geq 1\}$. Let $$D(f)=\big\{z\in \mathbb C:\overline{O^+(z)}=J(f)\big\}.$$ So $D(f)$ is the set of points whose (...
D.S. Lipham's user avatar
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2 votes
1 answer
107 views

Uniformization of Julia sets and lacunary series

If the complement of a Julia set of quadratic polynomial z^2+c is locally connected and simply connected, it is uniformized by the complement of the unit disk. Consider the uniformization map and its ...
0x11111's user avatar
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5 votes
1 answer
110 views

Jordan curve boundaries of Fatou components

Let $f:\mathbb C\to \mathbb C$ be a rational map and let $J(f)$ and $F(f)$ denote the Julia and Fatou sets of $f$, respectively. Let $\mathcal S$ be the set of all boundaries of Fatou components. ...
D.S. Lipham's user avatar
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-1 votes
1 answer
209 views

How does a connected Julia set imply a member of the Mandelbrot Set?

I'm doing an introductory online course in complex analysis. In one of the lectures its stated that a complex number $c$ belongs to the Mandelbrot Set iff the Julia set $J(z^2 + c)$ is connected. I ...
Informics's user avatar
16 votes
3 answers
1k views

If I have zeros at the vertices of an icosahedron, where should the poles go?

I've been tinkering with Newton's method applied to polynomials. E.g., Newton's method for $z^5 - 1 = 0$ gives: There aren't a lot of symmetric patterns of finite sets of points in the plane, so I ...
Geoffrey Irving's user avatar
4 votes
2 answers
368 views

Hausdorff dimension of Julia set

Can anyone show me the proof "Hausdorff dimension of Julia set is strictly positive"? For purpose to prove this we might have to prove the green function of basin of attraction to infinity ...
matthew's user avatar
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10 votes
1 answer
399 views

Convex Julia sets

Consider the classical Julia set $J_f$ associated with $f(z)=z^2+c$. Since $J_c$ is completely invariant, we know that $f^{-1}(J_f) \subseteq J_f$. Now, let $H_f$ be the convex hull of $J_f$. Is it ...
Per Alexandersson's user avatar
1 vote
1 answer
145 views

Is the set of non-escaping points in a Julia set always totally disconnected?

I am looking for examples of transcendental entire functions $f:\mathbb C\to \mathbb C$ such that the set of non-escaping points in the Julia set of $f$ is not totally disconnected. I denote this set $...
D.S. Lipham's user avatar
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5 votes
2 answers
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Who proved that the Mandelbrot set's Julia sets are locally connected?

I'd be greatly interested in a reference to the respective article. Was it Douady? Julia? Hubbard? Fatou? Bonus question: Who gave the proof that can be found in the Orsay notes? EDIT: The question ...
Cloudscape's user avatar
5 votes
1 answer
167 views

Is the function Point -> Julia set "injective"?

Consider the functions $f_c(z) := z^2 + c$ for $c \in \mathbb C$. For each such function, we may form the associated Julia set. My question: If $c, c' \in \mathbb C$ produce in this way the same Julia ...
Cloudscape's user avatar
27 votes
5 answers
4k views

Why are the Julia sets so simple? (quadratic family)

I want to know why, when I look at the Julia sets of the quadratic family, I see only a finite number of repeating patterns, rather than a countable infinity of them. My question is specifically ...
Andrea's user avatar
  • 381
13 votes
0 answers
305 views

Diophantine approximation in the Julia set

Let $f : \mathbb{CP}^1 \to \mathbb{CP}^1$ be a rational map of degree $q > 1$; or just a quadratic binomial $z^2 + c$, if one prefers. The Julia set $J_f$ is the closure of the repelling periodic ...
Vesselin Dimitrov's user avatar
9 votes
2 answers
1k views

Is this a Julia set (and if so, for which function family is it the Julia set)?

Consider the function family given by $f_\lambda(z) = z - p_\lambda(z)/p_\lambda'(z)$ where $p_\lambda(z) = (z^2 - 1)(z - \lambda)$. Every attracting cycle and every rational neutral cycle of $f_\...
Aaron Golden's user avatar
10 votes
1 answer
2k views

Area of filled Julia sets

The recent question Area of the boundary of the Mandelbrot set ? prompted me to ask this question. There has been some work on estimates for the area of the Mandelbrot set, e.g., a paper by John H. ...
lhf's user avatar
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