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<Paper uid="C92-1052">
  <Title>Temporal Structure of Discourse*</Title>
  <Section position="3" start_page="0" end_page="0" type="intro">
    <SectionTitle>
2 Temporal relations
</SectionTitle>
    <Paragraph position="0"> The semantic representation of an eventuality includes a time interval where the eventuality must be true so that the sentence and the discourse can be true. The time interval will be represented by two time points. Temporal relations between two time intervals can be expressed by relations between the extremes of the time intervals. So instead of using the 13 reintions proposed by Allen \[1\] we have chosen to use just 5 relations.</Paragraph>
    <Paragraph position="1">  These 5 relations are enough for translating natural language sentences as it is difficult to express the 13 relations of Allen and their 213 combinations in natural language. F. van Eynde \[6\] presents the set of relations necessary for the temporal systems he studied (for EEC languages). Our relation set, however, is smaller. As sentence aspect coerces the verb aspectual class to change \[16\], v. Eynde's overlap relations may be rewritten using the relations &lt; and &gt;.</Paragraph>
    <Paragraph position="2"> The following examples will demonstrate our use of the temporal relations. For the sake of simplicity only discourse referents introduced by eventualities and time intervals are represented. Eventualities introduced by nominals (as in example I &amp;quot;his key&amp;quot;) are discarded.</Paragraph>
    <Paragraph position="3"> I) John picked off his key(l). He opened the door(2).</Paragraph>
    <Paragraph position="4"> The eventualities of sentences (1)and (2) are: event(st, pick(john, key1}}, time(eht,~); event(e2, open(john, door1)), time(e2,tdeg2); the temporal relation is t,, &lt; t+ 2.</Paragraph>
    <Paragraph position="5"> lI) John bought an umbrella(l). He had lost his umbrella(2).</Paragraph>
    <Paragraph position="6"> The eventualities of sentences (1) and (2) are: event(el, buy(john, utah1)), time(ehtdeg,); event(e2, looseOohu, umb~)) , time(e2,tdeg~); the temporal relation is ts~ &gt; t,,.</Paragraph>
    <Paragraph position="7"> III) John bought an umbrella (1). It was raining(2). null The eventualities of sentence (1) and (2) are: event(et, buyOohn,umbl)) , time(ea,t,~); event(e2, rain), time(e2,t,,); the temporal relation is t,, C t,2.</Paragraph>
    <Paragraph position="8"> IV) John had a nice meal(l). He ate salmon(Z). The eventualities of sentence (1) and (2) are: event(el, have(john, meal)), time(el,tdegt); eventCe2, eat(john,salmon)), time(e2,t,,); the temporal relation is t,, D tdeg~.</Paragraph>
    <Paragraph position="9"> V) It was raining(I). There was a strong wind(2).</Paragraph>
    <Paragraph position="10"> A~ DE COLING-92, NANTES, 23-28 ^OUT 1992 3 3 2 PROC. OF COLING-92, NANTBS, AUO. 23-28, 1992 Tile eventualities of sentence (x) and (2) are: event(c1, rain), time(eht,,); event(e=, wind_stroug), time(e~,t0~); the temporal relation is t,, c~ tdeg~.</Paragraph>
    <Paragraph position="11"> V1) John sat down on a chair0}. Mary lied down on a sofa(2).</Paragraph>
    <Paragraph position="12"> The eventualities of sentence (1) and (2) are: event(el, sit(john, chair1)), time(el,t,,); event(e~, lie(Mary, sofa)), time(e~,t,~); the temporal relation is tst none to~ as these two eventualities are independent.</Paragraph>
  </Section>
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