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A Bag of Useful Techniques for Unification-Based Finite-State Transducers

Hans-Ulrich Krieger; Witold Drozdzynski; Jakub Piskorski; Ulrich Schäfer; Feiyu Xu
In: Proceedings of 7th KONVENS. Konferenz zur Verarbeitung natürlicher Sprache (KONVENS), Vienna, Pages 105-112, 9/2004.


We present several extensions to the shallow text processor sprout, viz.,
  1. a fast imperfect unifiability test,
  2. a special form of sets together with a polymorphic lazy and destructive unification operation,
  3. a cheap form of negation,
  4. a weak unidirectional form of coreferences,
  5. optional context-free stages in the shallow cascade,
  6. a compile time type check,
  7. compile time transition sorting under subsumption,
  8. several output merging techniques, and
  9. a compaction technique for lexical resources.
The extensions have been found relevant in several projects and might be of importance to other systems, even to deep processing.