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<Paper uid="J88-2005">
  <Title>A COMPUTATIONAL MODEL OF THE SEMANTICS OF TENSE AND ASPECT</Title>
  <Section position="15" start_page="52" end_page="52" type="concl">
    <SectionTitle>
6 CONCLUSION
</SectionTitle>
    <Paragraph position="0"> The situation representations presented here model the temporal meaning of inflected verbs by assigning a semantic value to each of four components; the inherent lexical aspect, the tense, and the presence or absence of 58 Computational Linguistics, Volume 14, Number 2, June 1988 Rebecca J. Passonneau A Computational Model of the Semantics of Tense and Aspect the perfect and progressive. Two significant advantages to the overall proposal are the simplicity of the algorithm that computes the representations, and the generality of the building blocks used in constructing them.</Paragraph>
    <Paragraph position="1"> The algorithm accounts for the context dependencies among the four semantic components through a single mechanism, i.e., an appropriate characterization of the event time and its relation to the full temporal structure of a state, process, or transition event. These temporal structures are composed of intervals that may be active or stative, and that may be bounded, unbounded, or unspecified for boundedness.</Paragraph>
    <Paragraph position="2"> The situation representations have certain advantages in and of themselves. For example, the linkage between the components of temporal structure and Dowty's aspect calculus, and the incorporation of a Reichenbachian treatment of tense, make it possible to represent very precisely what predicates hold when.</Paragraph>
    <Paragraph position="3"> Further, the dual possibility of associating the become operator either with an unbounded interval or a transition bound between intervals circumvents the so-called imperfective paradox. An additional advantage is the utility of these representations for further processing.</Paragraph>
    <Paragraph position="4"> The preceding section illustrated how the three building blocks of the representations (i.e., the notion of persistence of some situation through an interval, kinesis of the situation, and boundedness of the interval) make it possible to interpret accurately three corresponding kinds of temporal adverbials, and to identify those cases where coercion is required. Finally, explicit representation of the reference times and event times within distinct types of temporal structures should make it possible to account for the differential contribution of situations to narratives and other types of discourse.</Paragraph>
  </Section>
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