Julia Set

Gaston Maurice Julia (3 February 1893 to 19 March 1978) was a French mathematician who devised the formula for the Julia set.

Let R(z) be a rational function

R(z)=(P(z))/(Q(z)),

(1) where z in C^*, C^* is the Riemann sphere C union {infty}, and P and Q are polynomials without common divisors.

The "filled-in" Julia set J_R is the set of points z which do not approach infinity after R(z) is repeatedly applied (corresponding to a strange attractor).

The true Julia set J is the boundary of the filled-in set (the set of "exceptional points").