\begin{align*}
 h &:= a + i*b \\
 f_h &: \mathbb{C} \mapsto \mathbb{C} \\
 f_h(c + i*d) &:= (c^2 - d^2 + a) + i*(2 * c * d + b)
\end{align*}


\begin{align*}
 f_h( f_h( f_h( ... f_h(z) ) ) )
\end{align*}



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<img src="index.php?rex_img_type=rex_mediapool_maximized&rex_img_file=equation_composition.png" alt="Funktionskomposition" />

<img src="index.php?rex_img_type=rex_mediapool_maximized&rex_img_file=equation.png" alt="Gleichung Julia-Mengen" />