# Feigenbaum constant

There are two

mathematical constants called

**Feigenbaum constants**. Both express ratios in a

bifurcation diagram. is the

ratio between successive bifurcation intervals, or between the diameters of successive circles on the axis of the

Mandelbrot set. is the ratio between the width of a tine and the width of one of its two subtines (except the tine closest to the fold).

These numbers apply to a large class of dynamical systems, not just to the logistic map.

Both numbers are believed to be transcendental although they haven't been proven to be so.