Question 24
AUTOMATED PLANNING
The domain description of a Blocks World with a single one-armed robot is given below.
PREDICATES
armEmpty The arm is not holding any block, it is empty.holding(X) The arm is holding X.onTable(X) X is on the table.clear(X) X has nothing above it, it is clear.on(X,Y) X is directly placed on Y.OPERATORS
Pickup(X): pick up X from the table.
Preconditions: { armEmpty, clear(X), onTable(X) } Add Effects : { holding(X) } Del Effects : { armEmpty, onTable(X) }
Putdown(X): place X on the table.
Preconditions: { holding(X) } Add Effects : { armEmpty, onTable(X) } Del Effects : { holding(X) }
Unstack(X,Y): pick up X that is directly sitting on Y.
Preconditions: { armEmpty, clear(X), on(X,Y) } Add Effects : { clear(Y), holding(X) } Del Effects : { armempty, on(X,Y) }
Stack(X,Y): place X directly on top of Y.
Preconditions: { holding(X), clear(Y) } Add Effects : { armEmpty, on(X,Y) } Del Effects : { holding(X), clear(Y) }Consider the planning problem with the following start state and goal description.
Based on the above data, answer the given subquestions.
In the planning graph, which of the following are mutex proposition pairs in Layer 1?
clear (Q), armEmpty
holding (P), holding (R)
onTable (R), clear (R)
onTable (R), onTable (Q)