Compressed Pattern Matching for SEQUITUR

Sequitur due to Nevill-Manning and Witten. [18] is a powerful program to infer a phrase hierarchy from the input text, that also provides extremely effective compression of large quantities of semi-structured text [17]. In this paper, we address the problem of searching in Sequitur compressed text directly. We show a compressed pattern matching algorithm that finds a pattern in compressed text without explicit decompression. We show that our algorithm is approximately 1.27 times faster than a decompression followed by an ordinal search.