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<Paper uid="P92-1012">
  <Title>RECOGNITION OF LINEAR CONTEXT-FREE REWRITING SYSTEMS*</Title>
  <Section position="7" start_page="93" end_page="93" type="concl">
    <SectionTitle>
4 CONCLUSIONS
</SectionTitle>
    <Paragraph position="0"> We have studied the class LCFRS along two dimensions: the fan-out and the maximum right-hand side length. The recognition (membership) problem for LCFRS has been investigated, showing NP-hardness in all three cases in which at least one of the two dimensions above is unbounded. Some consequences of the main result have been discussed, among which the interesting relation between crossing configurations and parsing efficiency: it has been suggested that the addition of restrictions on these configurations should be seriously considered for the class LCFRS. Finally, the issue of the existence of efficient algorithms for the class r-LCFRS(k) has been addressed.</Paragraph>
  </Section>
class="xml-element"></Paper>