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<Paper uid="P95-1008">
  <Title>DATR Theories and DATR Models</Title>
  <Section position="1" start_page="0" end_page="0" type="abstr">
    <SectionTitle>
Abstract
</SectionTitle>
    <Paragraph position="0"> Evans and Gazdar (Evans and Gazdar, 1989a; Evans and Gazdar, 1989b) introduced DATR as a simple, non-monotonic language for representing natural language lexicons. Although a number of implementations of DATR exist, the full language has until now lacked an explicit, declarative semantics. This paper rectifies the situation by providing a mathematical semantics for DATR. We present a view of DATR as a language for defining certain kinds of partial functions by cases. The formal model provides a transparent treatment of DATR's notion of global context. It is shown that DA-I'R's default mechanism can be accounted for by interpreting value descriptors as families of values indexed by paths.</Paragraph>
  </Section>
class="xml-element"></Paper>