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<Paper uid="P91-1006">
  <Title>A THREE-LEVEL MODEL FOR PLAN EXPLORATION</Title>
  <Section position="3" start_page="0" end_page="39" type="intro">
    <SectionTitle>
THE NATURE
OF PLAN EXPLORATION
</SectionTitle>
    <Paragraph position="0"> Cohen and Levesque \[CLg0\] have recently pointed out the theoretical problems that arise, while using a planning system to model a rational agent, from failing to distinguish between a system's plans and its intentions, since agents frequently form plans that they never adopt. It is this same distinction that motivates the division proposed here of the domain-plan-related portion of the discourse model into separate levels representing first those domain plans and goals which the agent has adopted and is pursuing, here called the domain  layer, and second those which the agent is exploring but has not adopted, the exploration layer. While the same domain plans give structure to these two levels, the resulting discourse phenomena including the space of relevant queries based on those plans and the patterns of references to plans in the plan tree are quite different.</Paragraph>
  </Section>
class="xml-element"></Paper>