On the average sequence complexity

This paper discusses the measure of complexity of a sequence called the complexity index. The complexity index captures the "richness of the language" used in a sequence. The measure is simple but quite intuitive. Sequences with low complexity index contain a large number of repeated substrings and they eventually become periodic (e.g., tandem repeats in a DNA sequence). The complexity index is used to characterize the sequence statistically and has a long history of applications in several fields, such as data compression, computational biology, data mining, computational linguistics, among others.