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<Paper uid="W06-2706">
  <Title>Querying XML documents with multi-dimensional markup</Title>
  <Section position="4" start_page="49" end_page="49" type="metho">
    <SectionTitle>
4 Conclusion
XML documents with multi-dimensional
</SectionTitle>
    <Paragraph position="0"> markup feature a heterogeneous structure that depends on the algorithm for merging of concurrent markup. We present a pattern language that allows to abstract from the concrete structure of a document and formulate powerful queries. The extended sequence semantics allows matching of sequences across element borders and on different levels of the XML tree ignoring nesting levels irrelevant for the query. The formal specification of the sequence semantics guarantees that the properties of &amp;quot;classic&amp;quot; sibling sequence such as ordering, absence of gaps and overlaps between the neighbors are maintained. The combination of fully recursive backtracking patterns with the ENSS semantics allows complex queries reflecting the complicated positional and hierarchical dependencies of XML nodes within a multi-dimensional markup. Negation enhances the expressivity of the queries specifying an absence of a pattern in a certain context.</Paragraph>
  </Section>
class="xml-element"></Paper>