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<Paper uid="H05-1101">
  <Title>Proceedings of Human Language Technology Conference and Conference on Empirical Methods in Natural Language Processing (HLT/EMNLP), pages 803-810, Vancouver, October 2005. c(c)2005 Association for Computational Linguistics Some Computational Complexity Results for Synchronous Context-Free Grammars</Title>
  <Section position="1" start_page="0" end_page="0" type="abstr">
    <SectionTitle>
Abstract
</SectionTitle>
    <Paragraph position="0"> This paper investigates some computational problems associated with probabilistic translation models that have recently been adopted in the literature on machine translation. These models can be viewed as pairs of probabilistic contextfreegrammarsworkingina'synchronous' null way. Two hardness results for the class NP are reported, along with an exponential time lower-bound for certain classes of algorithms that are currently used in the literature.</Paragraph>
  </Section>
class="xml-element"></Paper>