
2.6 Comparisons 47
•
The negation in preconditions can be handled through a simple syntactical
change, as discussed in the following section (in the comparison between the
set-theoretic and the classical representations).
Furthermore, complex expressions on state variables, such as rload(r) = nil
or cpos(c) ∈{loc1, loc2}, can easily be introduced in preconditions and goals,
as will be illustrated in Section 8.3. Other extensions, similar to those discussed in
Section 2.4, can also be added to the state-variable representation.
Recall that here a state s is a tuple s ∈
x∈X
D
x
: we said that s is specified by
giving the value of every ground state variable ...