Parallel communicating pushdown automata systems

Erzsébet Csuhaj-Varjú, Carlos Martín-Vide, Victor Mitrana, György Vaszil

Research output: Contribution to journalArticle

19 Citations (Scopus)


We consider automata systems consisting of several pushdown automata working in parallel and communicating the contents of their stacks by request, using a communication strategy borrowed from grammar system theory. We investigate the computational power of these mechanisms. We prove that non-centralized parallel communicating pushdown automata systems with a bounded number of components, where each automaton is allowed to issue a query, are able to recognize all recursively enumerable languages. We also present homomorphical characterizations of the class of recursively enumerable languages for the centralized variants, where only a distinguished automaton issues queries. Moreover, we show that these centralized variants are at least as powerful as one-way multihead pushdown automata. Finally, some open problems and further directions of research are discussed.

Original languageEnglish
Pages (from-to)633-650
Number of pages18
JournalInternational Journal of Foundations of Computer Science
Issue number4
Publication statusPublished - Jan 1 2000


  • n-head pushdown automata
  • parallel communicating systems
  • pushdown automata
  • two-stack pushdown automata

ASJC Scopus subject areas

  • Computer Science (miscellaneous)

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