Knowledge Systems Laboratory, Stanford University
15
Infinity and Density
uInfinite-Past and Infinite-Future are time points
„Defining axiom:
>(and  (Time-Point Infinite-Past)
>          (=>   (Time-Point ?p)   (not  (Before ?p Infinite-Past))))
uThe time line is considered to be dense
„Defining axiom:
> (=>   (and  (Time-Point ?i)  (Time-Point ?j)  (Before ?i ?j))
>         (exists   ?k   (and  (Before ?i ?k)  (Before ?k ?j))))