Artificial Intelligence and Soft Computing: Behavioral ... - Arteimi.info

(B), we generate the old state 3, whose pre-conditions are all available in the
initial state. Thus the goal On(C, B) is satisfied.
On (A,B)
On (B, Table)
On (C, Table)
Clear (A)
Clear ( C )
Initial State Old State2
On( A,B)
Clear (A)
Add:
On(A, Table)
Clear (B )
Delete:
On (A,B )
Old State 3
Clear (C )
Clear (B )
On (B, Table)
Add: On (C,B )
Delete:
Clear B
Threatens
Fig.12.7: Demonstrating threatening of old state1 by old state 2.
On(B, A)
On (C, B)
On (A, Table)
Clear (C)
Old State1
Clear (B)
Goal State
Clear (A)
)
On ( B, Table)
Add:On (B,A)
Del: Clear (B)
Old State 1
Now, let us try to satisfy the On (B, A) in the goal. This fortunately
can be made available by the add-list of old state 1. But can we satisfy the
preconditions of old state 1? It is to be noted that the pre-conditions Clear(A)
and On (B, Table) are available in the initial state and have not been deleted
yet. But the third pre-condition Clear (B) of the state 1 has been deleted by old
state 2. In other words old state 2 [or the use of rule 3 (operator 3)] threatens
the link [Clear (B)] from old state 3 to old state 1. This has been represented
by dotted lines in fig. 12.7. The dependence of states with the threatening