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Deciding equivalence of finite tree automata

  • Helmut Seidl
Contributed Papers Formal Languages
Part of the Lecture Notes in Computer Science book series (LNCS, volume 349)

Abstract

We show: for every constant m it can be decided in polynomial time whether or not two m-ambiguous finite tree automata are equivalent. In general, inequivalence for finite tree automata is DEXPTIME-complete w.r.t. logspace reductions, and PSPACE-complete w.r.t. logspace reductions, if the automata in question are supposed to accept only finite languages. For finite tree automata with coefficients in a field R we give a polynomial time algorithm for deciding ambiguity-equivalence provided R-operations and R-tests for 0 can be performed in constant time. We apply this algorithm for deciding ambiguity-inequivalence of finite tree automata in randomized polynomial time.

Furthermore, for every constant m we show that it can be decided in polynomial time whether or not a given finite tree automaton is m-ambiguous.

Keywords

Polynomial Time Prime Number Turing Machine Polynomial Time Algorithm Finite 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.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1989

Authors and Affiliations

  • Helmut Seidl
    • 1
  1. 1.Fachbereich InformatikUniversität des SaarlandesSaarbrückenWest Germany

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