Hi Boaz:

>From boaz@ccs.neu.edu Wed Jun 11 23:24:08 1997
>
>our only tool for negation is the bypassing clause, or its bigger brother
>the edge predicate. 
>

That is fine, we can simulate negation with bypassing and other
edge predicates.

Some examples:

! A.B        = empty set
! A.B.C      = A . bypassing B C
! A.B.C.D    = A.bypassing B D + A.B.bypassing C D
! A.(B+C).D  = A.bypassing{B,C}.D
! do s1.do s2= do !s1 * do !s2 

-- Karl