International Symposium on Experimental Algorithms

SEA 2015: Experimental Algorithms pp 15-27

Tree Compression with Top Trees Revisited

Conference paper

DOI: 10.1007/978-3-319-20086-6_2

Volume 9125 of the book series Lecture Notes in Computer Science (LNCS)
Cite this paper as:
Hübschle-Schneider L., Raman R. (2015) Tree Compression with Top Trees Revisited. In: Bampis E. (eds) Experimental Algorithms. SEA 2015. Lecture Notes in Computer Science, vol 9125. Springer, Cham

Abstract

We revisit tree compression with top trees (Bille et al. [2]), and present several improvements to the compressor and its analysis. By significantly reducing the amount of information stored and guiding the compression step using a RePair-inspired heuristic, we obtain a fast compressor achieving good compression ratios, addressing an open problem posed by [2]. We show how, with relatively small overhead, the compressed file can be converted into an in-memory representation that supports basic navigation operations in worst-case logarithmic time without decompression. We also show a much improved worst-case bound on the size of the output of top-tree compression (answering an open question posed in a talk on this algorithm by Weimann in 2012).

Keywords

Tree compression Grammar compression Top trees XML compression 

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Copyright information

© Springer International Publishing Switzerland 2015

Authors and Affiliations

  1. 1.Institute of Theoretical Informatics, Karlsruhe Institute of TechnologyKarlsruheGermany
  2. 2.Department of Computer ScienceUniversity of LeicesterLeicesterUK