Random Generation and Approximate Counting of Ambiguously Described Combinatorial Structures

  • Alberto Bertoni
  • Massimiliano Goldwurm
  • Massimo Santini
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1770)


This paper concerns the uniform random generation and the approximate counting of combinatorial structures admitting an ambiguous description. We propose a general framework to study the complexity of these problems and present some applications to specific classes of languages. In particular, we give a uniform random generation algorithm for finitely ambiguous context-free languages of the same time complexity of the best known algorithm for the unambiguous case. Other applications include a polynomial time uniform random generator and approximation scheme for the census function of (i) languages recognized in polynomial time by one-way nondeterministic auxiliary pushdown automata of polynomial ambiguity and (ii) polynomially ambiguous rational trace languages.


uniform random generation approximate counting context-free languages auxiliary pushdown automata rational trace languages inherent ambiguity 


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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • Alberto Bertoni
    • 1
  • Massimiliano Goldwurm
    • 1
  • Massimo Santini
    • 1
  1. 1.Dipartimento di Scienze dell’InformazioneUniversità degli Studi di MilanoMilanoItalia

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