STOC '00 Proceedings of the thirty-second annual ACM symposium on Theory of computing
Compression of Low Entropy Strings with Lempel--Ziv Algorithms
SIAM Journal on Computing
An experimental study of an opportunistic index
SODA '01 Proceedings of the twelfth annual ACM-SIAM symposium on Discrete algorithms
Journal of Algorithms
Succinct representations of lcp information and improvements in the compressed suffix arrays
SODA '02 Proceedings of the thirteenth annual ACM-SIAM symposium on Discrete algorithms
Adding Compression to Block Addressing Inverted Indexes
Information Retrieval
Optimal Exact Strring Matching Based on Suffix Arrays
SPIRE 2002 Proceedings of the 9th International Symposium on String Processing and Information Retrieval
Indexing Text Using the Ziv-Lempel Trie
SPIRE 2002 Proceedings of the 9th International Symposium on String Processing and Information Retrieval
Proceedings of the 16th Conference on Foundations of Software Technology and Theoretical Computer Science
Succinct representation of balanced parentheses, static trees and planar graphs
FOCS '97 Proceedings of the 38th Annual Symposium on Foundations of Computer Science
Opportunistic data structures with applications
FOCS '00 Proceedings of the 41st Annual Symposium on Foundations of Computer Science
Indexing text using the Ziv-Lempel trie
Journal of Discrete Algorithms - SPIRE 2002
Representing Trees of Higher Degree
Algorithmica
ACM Computing Surveys (CSUR)
Approximate string matching with Lempel-Ziv compressed indexes
SPIRE'07 Proceedings of the 14th international conference on String processing and information retrieval
Reducing the space requirement of LZ-Index
CPM'06 Proceedings of the 17th Annual conference on Combinatorial Pattern Matching
A compressed self-index using a ziv-lempel dictionary
SPIRE'06 Proceedings of the 13th international conference on String Processing and Information Retrieval
Space-efficient construction of LZ-index
ISAAC'05 Proceedings of the 16th international conference on Algorithms and Computation
A Lempel-Ziv text index on secondary storage
CPM'07 Proceedings of the 18th annual conference on Combinatorial Pattern Matching
Practical approaches to reduce the space requirement of lempel-ziv--based compressed text indices
Journal of Experimental Algorithmics (JEA)
Space-efficient construction of Lempel-Ziv compressed text indexes
Information and Computation
On compressing and indexing repetitive sequences
Theoretical Computer Science
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The LZ-index is a theoretical proposal of a lightweight data structure for text indexing, based on the Ziv-Lempel trie. If a text of u characters over an alphabet of size σ is compressible to n symbols using the LZ78 algorithm, then the LZ-index takes 4n log2 n (1+o(1)) bits of space (that is, 4 times the entropy of the text) and reports the R occurrences of a pattern of length m in worst case time O(m3 log σ + (m + R)log n). In this paper we face the challenge of obtaining a practical implementation of the LZ-index, which is not at all straightforward from the theoretical proposal. We end up with a prototype that takes the promised space and has average search time O(σ m log u + &sqrt;uR). This prototype is shown to be faster than other competing approaches when we take into account the time to report the positions or text contexts of the occurrences found. We show in detail the process of implementing the index, which involves interesting lessons of theory versus practice.