The previous sections presented a formalism adequate for the examples discussed. In this section we discuss the situation calculus in general and its connection with the real world. We also discuss relations between different situation calculus theories, e.g. theories at different levels of detail,

with actions by agents as a special case. Thus an action term *a* is
considered an abbreviation of the event term *Does*(*person*,*a*).
Besides *effect axioms* formalizing *Result*(*e*,*s*) [*do*(*e*,*s*) in
Canada and its colonies], there are *occurrence axioms* asserting
that in situations satisfying certain expressions in the fluents, an
event *e* occurs--written *Occurs*(*e*,*s*).

Before giving effect and occurrence axioms, we present some general considerations concerning situation calculus and its applications.

Fri Feb 8 17:29:20 PST 2002