Knowledge Systems Laboratory, Stanford University
21
Styles of Temporal Representations
uQualification by time
„Functions and relations have a time argument
>E.g., (Married Joe Anne 1993)  [I.e., “Joe and Anne were married during 1993.”]
>Situation calculus
„Objects have time intervals associated with them
>E.g., Joe-Anne-Marriage
>            Documentation:  “A marriage of Joe and Anne during 1993”
>            Instance-Of:  Marriage
>            Husband:  Joe
>            Wife:  Anne
>            Time-Of:  1993
uSentences “hold true” at times
„E.g., (holds  (Married Joe Anne)  1993)  [I.e., “Joe and Anne were married during 1993.”]
uTense logics
„E.g., (F  (Married Joe Anne))  [I.e., “Joe and Anne will be married at some future time.”]
„     (F    (and   (not  (Married Joe Anne))
„                           (P  (Married Joe Anne))))
> [I.e., “At some future time Joe and Anne will have been married and will not be married.”]