# Glossary

## k-fold substring

A $k$-fold substring of a string $s$ is a repeated substring of $s$ that appears at least $k$ times in $s$. As an example, "CAT" is a 2-fold substring of "GCATTTCATGG", and "AA" is a 4-fold substring of "AAAAA" (note that we count overlapping occurrences of the substring).