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Equivalence of finite-valued bottom-up finite state tree transducers is decidable

  • Helmut Seidl
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 431)

Abstract

A bottom-up finite state tree transducer (FST) A is called k-valued iff for every input tree there are at most k different output trees. A is called finite-valued iff it is k-valued for some k. We show: it is decidable for every k whether or not a given FST A is k-valued, and it is decidable whether or not A is finite-valued. We give an effective characterization of all finite-valued FST's and derive a (sharp) upper bound for the valuedness provided it is finite. We decompose a finite-valued FST A into a finite number of single-valued FST's. This enables us to prove: it is decidable whether or not the translation of an FST A is included in the translation of a finite-valued FST A'.

Keywords

Input Tree Tree Automaton Tree Transducer Attribute Grammar Abstract Syntax Tree 
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 1990

Authors and Affiliations

  • Helmut Seidl
    • 1
  1. 1.Fachbereich InformatikUniversität des SaarlandesSaarbrücken 11West-Germany

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