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<Paper uid="A00-2033">
  <Title>Removing Left Recursion from Context-Free Grammars</Title>
  <Section position="8" start_page="253" end_page="253" type="concl">
    <SectionTitle>
6 Conclusions
</SectionTitle>
    <Paragraph position="0"> We have shown that, in its textbook form, the standard algorithm for eliminating left recursion from CFGs is impractical for three diverse, independently-motivated, natural-language grammars. We apply a number of optimizations to the algorithm--most notably a novel strategy for ordering the nonterminals of the grammar--but one of the three grammars remains essentially intractable.</Paragraph>
    <Paragraph position="1"> We then explore an alternative approach based on the LC grammar transform. With several optimizations of this approach, we are able to obtain quite compact non-left-recursive forms of all three grammars. Given the diverse nature of these grammars, we conclude that our techniques based on the LC transform are likely to be applicable to a wide range of CFGs used for natural-language processing.</Paragraph>
  </Section>
class="xml-element"></Paper>