If a sequence has the property that the block growth function 
for all 
,
then it is said to have minimal block growth, and the sequence is called a Sturmian
sequence. An example of this is the sequence arising from the substitution
system
 |  |  |
(1)
|
 |  |  |
(2)
|
yielding 
,
which gives us the Sturmian sequence 01001010....
Sturm functions are sometimes also said to form a Sturmian sequence.
