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. The result of a Grasp is that the monkey holds the object if the monkey and object are in the same place at the same height.

Push action of the above monkey-and-bananas problem;

Action (Push(b, x, y),

PRECONDITION: At (Monkey, x) Can Push(b)

EFFECT: At(b, y) At (Monkey, y) At(b, x) At(Monkey, x))

Question: If the object is too heavy, its position will remain the same when the Push scheme is applied. I would like the above action scheme to be corrected to account for heavy objects.