Compressed index for dynamic text

This paper investigates how to index a text which is subject to updates. The best solution in the literature (P.Ferragina, et al., 1998) is based on suffix tree using O(n log n) bits of storage, where n is the length of the text. It supports finding all occurrences of a pattern P in O(|P|+occ) time, where occ is the number of occurrences. Each text update consists of inserting or deleting a substring of length y and can be supported in O(y+√(n)) time. In this paper, we initiate the study of compressed index using only O(n log |Σ|) bits of space, where Σ denotes the alphabet. Our solution supports finding all occurrences of a pattern P in O(|P| Iog²n(log^εn+log|Σ|)+occlog^1+εn) time, while insertion or deletion of a substring of length y can be done in O((y+√(n)) Iog^2+ε n) amortized tune, where 0<ε≤1. The core part of our data structure is based on the recent work on compressed suffix trees (CST) and compressed suffix arrays (CSA).