Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!mcvax!epg
From: epg@mcvax.cwi.nl (Ed Gronke)
Newsgroups: comp.graphics
Subject: Re: What's a Julia set?
Message-ID: <257@sering.mcvax.cwi.nl>
Date: Fri, 15-May-87 05:28:25 EDT
Article-I.D.: sering.257
Posted: Fri May 15 05:28:25 1987
Date-Received: Sun, 17-May-87 00:15:24 EDT
References: <165500002@uiucdcsb>
Reply-To: epg@sering.UUCP (Ed Gronke)
Organization: CWI, Amsterdam
Lines: 17
Keywords: Julia set, complex analytic dynamics, iterative maps

A Julia set , according to "An Introduction to Chaotic Dynamical Systems"
by Robert L. Devaney, Benjamin Cummings Publishing, 1986, ISBN # 0-8053-1601-9,
is defined by:

"Let P: C -> C be a polynomial. The Julia set of P, denoted by J(P), is the
closure of the set of repelling periodic points of P."

where C = the complex plane.
Also, a periodic point of perion n is repelling if the absolute value (modulus?)
of the derivative on the n iterate at the periodic point is > 0. i.e., 

     n            n
z = p (z ) and |(p )'(z )| > 1
 0      0              0


-- Ed Gronke epg@cwi.nl