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<Paper uid="C90-3017">
  <Title>A Symmetrical Approach to Parsing and Generation</Title>
  <Section position="6" start_page="0" end_page="0" type="concl">
    <SectionTitle>
6. Conclusion
</SectionTitle>
    <Paragraph position="0"> This paper shows that parsing and generation can be seen as symmetrical, or dual, processes exploiting one and the same grammar and lexicon, and using a basic l&lt;ft-recursion elimination transformation.</Paragraph>
    <Paragraph position="1"> Emphasis is on the simplicity and symmetry of linguistic description, which is mostly contained in the lexicon; compositionality appears under three aspects: string compositionality, semantic compositionality, and syntactic compositionality. The analysis and generation processes each favor one aspect: string compositionality in analysis, semantic compositionality in generation. These give rise to two guides (analysis guide and generation guide), which are generalizations of string indexes. The left-recursion elimination transformation described in the paper is stated using the general notion of guide, and is provably guaranteed, under certain explicit conditions, to lead to termination of the parsing and generation processes. We claim that the approach provides a simple, yet powerful solution to the problem of grammatical bidirectionality, and are currently testing it as a possible replacement for a more rule-oriented 19 A counter-example to this simplistic assumption is not hard to come by: the person who I john persuaded e I PRO to drink. However, the assumption gives the flavor of a possible set of strategies for handling empty categories. grammatical component in the context of the CRITTER translation system \[!DM88\].</Paragraph>
  </Section>
class="xml-element"></Paper>