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<Paper uid="P01-1044">
  <Title>Parsing with Treebank Grammars: Empirical Bounds, Theoretical Models, and the Structure of the Penn Treebank</Title>
  <Section position="8" start_page="0" end_page="0" type="concl">
    <SectionTitle>
5 Conclusion
</SectionTitle>
    <Paragraph position="0"> We built simple but accurate models on the basis of two observations. First, passive saturation is relatively constant in span size, but largedue to high reachability among phrasal categories in the grammar. Second, active saturation grows with span size because, as spans increase, thetags in agivenactiveedgeare more likely to find a matching arrangement over a span. Combining these models, we demonstrated that a wide range of empirical qualitative and quantitative behaviors of an exhaustive parser could be derived, including the potential super-cubic traversal growth over sentence lengths of interest.</Paragraph>
  </Section>
class="xml-element"></Paper>