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, ..., 
.
