AUTOMATED PLANNING The domain description of a Blocks World with a single one-armed robot is given below. Note: this is the same domain description used in the weekly assignments. 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) } Tie-breaker: When actions are chosen non-deterministically, choose actions that lead to a plan. Throw away the actions that lead to dead-ends or cycles. Tie-breaker: Treat the goal description, preconditions and effects as lists that are accessed from left to right. When the elements in a list are pushed one by one to a stack, the last element in the list will be at the top of the stack. It has the effect of reversing the list. A planning problem is given below, find a pla…

(D) onTable(C); on(A,B); onTable(B); { onTable(B), on(A,B), onTable(C) }; BOTTOM

(A) { onTable(B), on(A,B), onTable(C) }; onTable(B); on(A,B); onTable(C); BOTTOM

(B) { onTable(B), on(A,B), onTable(C) }; onTable(C); on(A,B); onTable(B); BOTTOM

(C) onTable(B); on(A,B); onTable(C); { onTable(B), on(A,B), onTable(C) }; BOTTOM

AI: Search Methods for Problem Solving · Quiz 2 · 23 Nov 2025 · September 2025 term

Question 24: AUTOMATED PLANNING The domain description of a Blocks Wo…

Question 24

+1 markOne correct option

AUTOMATED PLANNING

The domain description of a Blocks World with a single one-armed robot is given below.

Note: this is the same domain description used in the weekly assignments.

text

1PREDICATES
2
3armEmpty         The arm is not holding any block, it is empty.
4holding(X)       The arm is holding X.
5onTable(X)       X is on the table.
6clear(X)         X has nothing above it, it is clear.
7on(X,Y)          X is directly placed on Y.
8
9OPERATORS
10
11Pickup(X): pick up X from the table.
12      Preconditions: { armEmpty, clear(X), onTable(X) }
13      Add Effects  : { holding(X) }
14      Del Effects  : { armEmpty, onTable(X) }
15
16Putdown(X): place X on the table.
17      Preconditions: { holding(X) }
18      Add Effects  : { armEmpty, onTable(X) }
19      Del Effects  : { holding(X) }
20
21Unstack(X,Y): pick up X that is directly sitting on Y.
22      Preconditions: { armEmpty, clear(X), on(X,Y) }
23      Add Effects  : { clear(Y), holding(X) }
24      Del Effects  : { armempty, on(X,Y) }
25
26Stack(X,Y): place X directly on top of Y.
27      Preconditions: { holding(X), clear(Y) }
28      Add Effects  : { armEmpty, on(X,Y) }
29      Del Effects  : { holding(X), clear(Y) }

Tie-breaker: When actions are chosen non-deterministically, choose actions that lead to a plan. Throw away the actions that lead to dead-ends or cycles.

Tie-breaker: Treat the goal description, preconditions and effects as lists that are accessed from left to right. When the elements in a list are pushed one by one to a stack, the last element in the list will be at the top of the stack. It has the effect of reversing the list.

A planning problem is given below, find a plan using the operators and predicates defined in the blocks-world domain.

Start: { clear(A), clear(B), holding(A), on(B,C), onTable(C) }

Goal Description: { onTable(B), on(A,B), onTable(C) }

Based on the above data, answer the given subquestions.

Which of the following can be pushed as the first three elements onto the stack by the Goal Stack Planning algorithm? In the stack representation, the bottom is on the right side marked by the entry BOTTOM. Use appropriate tie-breakers listed in the main data.

A
{ onTable(B), on(A,B), onTable(C) }; onTable(B); on(A,B); onTable(C); BOTTOM
B
{ onTable(B), on(A,B), onTable(C) }; onTable(C); on(A,B); onTable(B); BOTTOM
C
onTable(B); on(A,B); onTable(C); { onTable(B), on(A,B), onTable(C) }; BOTTOM
D
onTable(C); on(A,B); onTable(B); { onTable(B), on(A,B), onTable(C) }; BOTTOM

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Correct answer

D
onTable(C); on(A,B); onTable(B); { onTable(B), on(A,B), onTable(C) }; BOTTOM

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Question 24 of 25 in the IIT Madras BS AI: Search Methods for Problem Solving (AI Search Methods) Quiz 2 paper sat on 23 Nov 2025, in the September 2025 term (IIT M IMPROVEMENT AN EXAM QIA2 23 Nov 2025). It carries 1 mark.

Question 24: AUTOMATED PLANNING The domain description of a Blocks Wo…

Question 24

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