Composition Closure of Linear Weighted Extended Top-Down Tree Transducers

  • Zoltán Fülöp
  • Andreas MalettiEmail author
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 11601)


Linear weighted extended top-down tree transducers with regular look-ahead and with weights from a semiring are formal models that are used in syntax-based statistical machine translation. The composition hierarchies of some restricted versions of such weighted tree transducers (also without regular look-ahead) are considered. In particular, combinations of the restrictions of \(\varepsilon \)-freeness (all rules consume input), nondeletion, and strictness (all rules produce output) are considered. The composition hierarchy is shown to be finite for all but one \(\varepsilon \)-free variant of these weighted transducers over any commutative semiring.


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© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Department of Foundations of Computer ScienceUniversity of SzegedSzegedHungary
  2. 2.Department of Mathematics and Computer ScienceUniversität LeipzigLeipzigGermany

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