The diameter of a set is the maximum distance
between any pair of points in the set. |
For example, the diameter of a circle is just
the common notion of diameter; the diameter of a square is the diagonal length of the
square. |
![](DiamEx.gif) |
Some diameters |
|
Because all the IFS rules are contractions,
the diameter of a region of address length
N goes to 0 as N goes to infinity. |
We illustrate this with the four transformations |
T3(x, y) = (x/2, y/2) + (0, 1/2) |
T4(x, y) = (x/2, y/2) + (1/2, 1/2) |
T1(x, y) = (x/2, y/2) |
T2(x, y) = (x/2, y/2) + (1/2, 0) |
|
As an IFS, these generate the unit square, S. We see |
![](DiamEx2.gif) |
  diam(S) = √2 |
  diam(Ti(S)) = (√2)/2 |
  diam(TjTi(S)) = (√2)/4 |
and in general |
  diam(TiN...Ti1(S)) =
(√2)/(2N) |
Consequently, diam(TiN...Ti1(S)) → 0
as N → ∞. |