Window Subsequence Problems for Compressed Texts

Given two strings (a text t of length n and a pattern p) and a natural number w, window subsequence problems consist in deciding whether p occurs as a subsequence of t and/or finding the number of size (at most) w windows of text t which contain pattern p as a subsequence, i.e. the letters of pattern p occur in the text window, in the same order as in p, but not necessarily consecutively (they may be interleaved with other letters). We are searching for subsequences in a text which is compressed using Lempel-Ziv-like compression algorithms, without decompressing the text, and we would like our algorithms to be almost optimal, in the sense that they run in time O(m) where m is the size of the compressed text. The pattern is uncompressed (because the compression algorithms are evolutive: various occurrences of a same pattern look different in the text).

• Type: Conference
• Year: 2006
• Where: CSR
• Authors: Patrick Cégielski, Irène Guessarian, Yury Lifshits, Yuri Matiyasevich
• Keywords: CSR 2006, Natural Number W, Pattern P, Theoretical Computer Science, Window Subsequence Problems