AI 3


2010 p4q2

2007 p4q7

2006 p4q4

2005 p4q4

2000 p9q9


The monkey-and-bananas problem is faced by a monkey in a laboratory with some 

bananas hanging out of reach from the ceiling. A box is available that will enable the monkey 

to reach the bananas if he climbs on it. Initially, the monkey is at A, the bananas at B, and the 

box at C . The monkey and box have height Low , but if the monkey climbs onto the box he 

will have height High , the same as the bananas. The actions available to the monkey include 

Go from one place to another, Push an object from one place to another, ClimbUp onto or ClimbDown from an object, and Grasp or Ungrasp an object. Grasping results in holding 

the object if the monkey and object are in the same place at the same height. 

a. Write down the initial state description. 

b. Write down STRIPS-style definitions of the six actions. 

c. Suppose the monkey wants to fool the scientists, who are off to tea, by grabbing the 

bananas, but leaving the box in its original place. Write this as a general goal (i.e., not 

assuming that the box is necessarily at C) in the language of situation calculus. Can this 

goal be solved by a S T R I P S-style system? 

d. Your axiom for pushing is probably incorrect, because if the object is too heavy, its 

position will remain the same when the Push operator is applied. Is this an example of 

the ramification problem or the qualification problem? Fix your problem description to 

account for heavy objects. 


(From Russel and Norvig, ch 11: available on-line)