Compressed Tree Canonization

  • Markus LohreyEmail author
  • Sebastian Maneth
  • Fabian Peternek
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9135)


Straight-line (linear) context-free tree (slt) grammars have been used to compactly represent ordered trees. Equivalence of slt grammars is decidable in polynomial time. Here we extend this result and show that isomorphism of unordered trees given as slt grammars is decidable in polynomial time. The result generalizes to isomorphism of unrooted trees and bisimulation equivalence. For non-linear slt grammars which can have double-exponential compression ratios, we prove that unordered isomorphism and bisimulation equivalence are \(\textsc {pspace}\)-hard and in \(\textsc {exptime}\).


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Aho, A., Hopcroft, J.E., Ullman, J.D.: The Design and Analysis of Computer Algorithms. Addison-Wesley, Reading (1974)zbMATHGoogle Scholar
  2. 2.
    Balcázar, J., Gabarró, J., Sántha, M.: Deciding bisimilarity is P-complete. Formal Aspects of Computing 4, 638–648 (1992)zbMATHCrossRefGoogle Scholar
  3. 3.
    Brenguier, R., Göller, S., Sankur, O.: A comparison of succinctly represented finite-state systems. In: Koutny, M., Ulidowski, I. (eds.) CONCUR 2012. LNCS, vol. 7454, pp. 147–161. Springer, Heidelberg (2012) CrossRefGoogle Scholar
  4. 4.
    Busatto, G., Lohrey, M., Maneth, S.: Efficient memory representation of XML document trees. Inf. Syst. 33(4–5), 456–474 (2008)CrossRefGoogle Scholar
  5. 5.
    Buss, S.R.: Alogtime algorithms for tree isomorphism, comparison, and canonization. Kurt Gödel Colloquium 97, 18–33 (1997)MathSciNetGoogle Scholar
  6. 6.
    Charikar, M., Lehman, E., Lehman, A., Liu, D., Panigrahy, R., Prabhakaran, M., Sahai, A., Shelat, A.: The smallest grammar problem. IEEE Trans. Inf. Theory 51(7), 2554–2576 (2005)zbMATHMathSciNetCrossRefGoogle Scholar
  7. 7.
    Das, B., Scharpfenecker, P., Torán, J.: Succinct encodings of graph isomorphism. In: Dediu, A.-H., Martín-Vide, C., Sierra-Rodríguez, J.-L., Truthe, B. (eds.) LATA 2014. LNCS, vol. 8370, pp. 285–296. Springer, Heidelberg (2014) CrossRefGoogle Scholar
  8. 8.
    Galperin, H., Wigderson, A.: Succinct representations of graphs. Inf. Contr. 56, 183–198 (1983)zbMATHMathSciNetCrossRefGoogle Scholar
  9. 9.
    Jenner, B., Köbler, J., McKenzie, P., Torán, J.: Completeness results for graph isomorphism. J. Comput. Syst. Sci. 66(3), 549–566 (2003)zbMATHCrossRefGoogle Scholar
  10. 10.
    Lengauer, T., Wagner, K.W.: The correlation between the complexities of the nonhierarchical and hierarchical versions of graph problems. J. Comput. Syst. Sci. 44, 63–93 (1992)zbMATHMathSciNetCrossRefGoogle Scholar
  11. 11.
    Lindell, S.: A logspace algorithm for tree canonization (extended abstract). In: Proc. STOC 1992, pp. 400–404. ACM (1992)Google Scholar
  12. 12.
    Lohrey, M.: Algorithmics on SLP-compressed strings: a survey. Groups Complexity Cryptology 4(2), 241–299 (2012)zbMATHMathSciNetCrossRefGoogle Scholar
  13. 13.
    Lohrey, M., Maneth, S., Peternek, F.: Compressed tree canonization (2015).
  14. 14.
    Lohrey, M., Maneth, S., Schmidt-Schauß, M.: Parameter reduction and automata evaluation for grammar-compressed trees. J. Comput. Syst. Sci. 78(5), 1651–1669 (2012)zbMATHCrossRefGoogle Scholar
  15. 15.
    Lohrey, M., Mathissen, C.: Isomorphism of regular trees and words. Inf. Comput. 224, 71–105 (2013)zbMATHMathSciNetCrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Markus Lohrey
    • 1
    Email author
  • Sebastian Maneth
    • 2
  • Fabian Peternek
    • 2
  1. 1.Universität SiegenSiegenGermany
  2. 2.University of EdinburghEdinburghUK

Personalised recommendations