The restricted growth string of a set partition of 
elements is the 
-character
string 
in which each character gives the set block (
, 
,
...) containing the corresponding element. It is sometimes called the restricted
growth function. For example, for the set partition 
, the restricted growth string would be
0122. If the set blocks are "sorted" so that
, then the restricted growth string satisfies the
inequality
 |
for 
, 2, ..., 
.
