Action -> effects or preconditions (usually not very useful):
Mary bought a stereo. -> Mary owns a stereo.
Mary was in a store that sells stereos.
Action -> action with effect of first action as precondition (but
there may be too many of these to consider):
Mary bought a stereo. -> Mary can listen to music.
Mary can disturb her neighbors late at night.
Script -> script step or goal:
Mary wanted to fly to New York. -> Mary bought a plane ticket.
Plan step -> plan; plan -> plan step or goal:
Mary found a screwdriver. -> She wanted to take something apart.
Matching Expectations with Interpretations
Example
Mary took out a fork. Then she polished off the leftover pie in the
refrigerator
Expectation: Mary eats something.
Interpretation1: Somebody eats (completely) some pie.
Interpretation2: Somebody shines some pie.
It is impossible to prove the expectation from either of
the interpretations because there is no way to know that Mary is
the "somebody" and the pie the "something". It is impossible to prove
either interpretation from the expectation for the same reasons.
Using unification and equality assertions: checking for consistency
of expectation and interpretation
Attempt to unify expectation