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<Paper uid="C90-2060">
  <Title>HOW TO INVERT A NATURAL LANGUAGE PARSER INTO AN EFFICIENT GENERATOR: AN ALGORITHM FOR LOGIC GRAMMARS</Title>
  <Section position="3" start_page="0" end_page="0" type="intro">
    <SectionTitle>
INTRODUCTION
</SectionTitle>
    <Paragraph position="0"> In this paper we describe the results obtained from the experiment with reversing a PROLOG parser for a substantial subset of English into an efficient generator. The starting point of the experiment was a string parser for English (Grishman, 1986), which is used in an English-Japanese MT project. The PROLOG version of this parser was inverted, using the method described here, into an efficient PROLOG generator working from regularized parse forms to English sentences. To obtain a PROLOG parser (or any PROLOG program) working in the reverse, requires ~ some manipulation of the clauses, especially the ordering of the literals on their right-hand side, as noted by Dymetman and Isabelle (1988). We do not discuss here certain other translbrmations used to &amp;quot;normalize&amp;quot; the parser code in order to attain maximum efficiency of the derived generator progrmn (Strzalkowski, 1989).</Paragraph>
  </Section>
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