Abstract
In this paper we explore the notion of periods of a string. A period can be thought of as a shift that causes the string to match over itself. We obtain two sets of necessary and sufficient conditions for a set of integers to be the set of periods of some string (what we call the correlation of the string). We show that the number of distinct correlations of length n is independent of the alphabet size and is of order nlogn. By using generating function methods we enumerate the strings having a given correlation, and investigate certain related questions.
Original language | English (US) |
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Pages (from-to) | 19-42 |
Number of pages | 24 |
Journal | Journal of Combinatorial Theory, Series A |
Volume | 30 |
Issue number | 1 |
DOIs | |
State | Published - Jan 1981 |