Complexity Results on Balanced Context-Free Languages

  • Akihiko Tozawa
  • Yasuhiko Minamide
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4423)


Some decision problems related to balanced context-free languages are important for their application to the static analysis of programs generating XML strings. One such problem is the balancedness problem which decides whether or not the language of a given context-free grammar (CFG) over a paired alphabet is balanced. Another important problem is the validation problem which decides whether or not the language of a CFG is contained by that of a regular hedge grammar (RHG). This paper gives two new results; (1) the balancedness problem is in PTIME; and (2) the CFG-RHG containment problem is 2EXPTIME-complete.


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Copyright information

© Springer Berlin Heidelberg 2007

Authors and Affiliations

  • Akihiko Tozawa
    • 1
  • Yasuhiko Minamide
    • 2
  1. 1.IBM Research, Tokyo Research Laboratory, IBM Japan, Ltd. 
  2. 2.Department of Computer Science, University of Tsukuba 

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