Block-Synchronization Context-Free Grammars

  • Helmut Jürgensen
  • Kai Salomaa


We consider context-free type block-synchronization grammars, BSCF grammars, where independent derivations can communicate using nested synchronization conditions. We prove inclusion relations between the language families defined by grammars using, respectively, the weak and strong prefix- or equality-synchronized derivation mode. In particular, the weak BSCF languages are strictly included in the family of strong BSCF languages for both the prefix- and equality-synchronized derivation mode. We can effectively decide whether the language generated by a weak BSCF grammar is empty.


Derivation Tree Empty Word Language Family Synchronization Condition Tree Automaton 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. [1]
    Aho A.V. Indexed grammars — An extension of context-free grammars. J. ACM 15 (1968) 647–671.MathSciNetMATHCrossRefGoogle Scholar
  2. [2]
    Dassow J., Păun G. Regulated Rewriting in Formal Language Theory. EATCS Monographs in Theoretical Computer Science, Vol. 18. Berlin: Springer-Verlag, 1989.Google Scholar
  3. [3]
    Engelfriet J., Schmidt E.M. I0 and OI. J. Comput System Sci. 15 (1977) 328- 353: 16 (1978) 67–99.Google Scholar
  4. [4]
    Fischer M.J. Grammars with macro like productions. Proceedings of the 9th Annual IEEE Symposium on Switching and Automata Theory; 1968, 131–142.Google Scholar
  5. [5]
    Gécseg F., Steinby M. Tree Automata. Budapest: Akadémiai Kiadó, 1984.MATHGoogle Scholar
  6. [6]
    Guessarian I. Pushdown tree automata. Math. Systems Theory 16 (1983) 237– 263MathSciNetCrossRefGoogle Scholar
  7. [7]
    Hayashi T. On derivation trees of indexed grammars — An extension of the uvwxy-theorem. Publ. RIMS, Kyoto Univ. 9 (1973) 61–92.MATHCrossRefGoogle Scholar
  8. [8]
    Hopcroft J.E., Ullman J.D. Introduction to Automata Theory, Languages, and Computation. Reading, MA: Addison-Wesley, 1979.Google Scholar
  9. [9]
    Hromkovič J. How to organize the communication among parallel processes in alternating computations. Unpublished manuscript, Comenius University, Bratislava, 1986Google Scholar
  10. [10]
    Hromkovič J., Karhumaki J., Rovan B., Slobodová A. On the power of synchro-nization in parallel computations. Discrete Appl. Math. 32 (1991) 155–182.MathSciNetMATHCrossRefGoogle Scholar
  11. [11]
    Hromkovič J., Rovan B., Slobodová A. Deterministic versus nondeterministic space in terms of synchronized alternating machines. Theoret. Comput. Sci. 132 (1994) 319–336.MathSciNetMATHCrossRefGoogle Scholar
  12. [12]
    Rounds W. Mappings and grammars on trees. Math. Systems Theory 4 (1970) 257–287.MathSciNetMATHCrossRefGoogle Scholar
  13. [13]
    Salomaa A. Formal Languages. New York: Academic Press, 1973.MATHGoogle Scholar
  14. [14]
    Salomaa K. Synchronized tree automata., Theoret. Comput. Sci. 127 (1994) 25–51.MathSciNetMATHCrossRefGoogle Scholar
  15. [15]
    Salomaa K. Decidability of equivalence for deterministic synchronized tree au-tomata. Proceedings of TAPSOFT-CAAP’95, Lect. Notes Comput. Sci. 915, Springer-Verlag, 1995, 140 - 154.Google Scholar

Copyright information

© Kluwer Academic Publishers 1997

Authors and Affiliations

  • Helmut Jürgensen
    • 1
  • Kai Salomaa
    • 1
  1. 1.Department of Computer ScienceUniversity of Western OntarioLondonCanada

Personalised recommendations