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Mathematical systems theory

, Volume 27, Issue 4, pp 285–346 | Cite as

Equivalence of finite-valued tree transducers is decidable

  • H. Seidl
Article

Abstract

A bottom-up finite state tree transducer (FST) M is calledk-valued iff for every input tree there are at mostk different output trees.M is called finite-valued iff it isk-valued for somek. We show that it is decidable for everyk whether or not a given FST M isk-valued. We give an effective characterization of all finite-valued FSTs and derive a (sharp) upper bound for the valuedness provided it is finite. We decompose a finite-valued FSTM into a finite number of single-valued FSTs. This enables us to prove: it is decidable whether or not the translation of an FSTM is included in the translation of a finite-valued FSTM'. We also consider these questions for size-valuedness.

Keywords

State Tree Computational Mathematic Finite Number Input Tree Output 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 New York Inc. 1994

Authors and Affiliations

  • H. Seidl
    • 1
  1. 1.Fachbereich InformatikUniversität des SaarlandesSaarbrückenGermany

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