Mandelbrot set
The Mandelbrot set () is a two-dimensional set. It is defined in the complex plane as the complex numbers c {\displaystyle c} for which the function f c ( z ) = z 2 + c {\displaystyle f_{c}(z)=z^{2}+c} does not diverge to infinity when iterated starting at z = 0 {\displaystyle z=0} .