Mathematical systems theory

, Volume 21, Issue 1, pp 125–145 | Cite as

Variants of top-down tree transducers with look-ahead

  • Zoltán Fülöp
  • Sándor Vágvölgyi


In this article we consider deterministic and strongly deterministic top-down tree transducers with regular look-ahead, with regular check, with deterministic top-down look-ahead, and with deterministic top-down check. We compare the transformational power of these tree transducer classes by giving a correct inclusion diagram of the tree transformation classes induced by them. Along with the comparison we decompose some of the examined classes into simpler classes and we introduce the concept of the deterministic top-down tree automata with deterministic top-down look-ahead. We show that these recognizers recognize a tree language class which is strictly between the class of regular tree languages and the class of tree languages recognizable by deterministic top-down tree automata. We also study the closure properties of the examined tree transformation classes. We show that some classes are closed under composition while others, for example the class of tree transformations induced by deterministic top-down tree transducers with deterministic top-down look-ahead, are not.


Function Symbol Closure Property Input Tree Tree Automaton Tree Language 
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Copyright information

© Springer-Verlag New York Inc 1988

Authors and Affiliations

  • Zoltán Fülöp
    • 1
  • Sándor Vágvölgyi
    • 1
  1. 1.Research Group on Theory of AutomataHungarian Academy of SciencesSzegedHungary

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