Question 15
GOAL STACK PLANNING
The domain description of Blocks World with a single one-armed robot is given below.
Tie-breaker 1: Treat the goal description, preconditions and effects as lists that are accessed from left to right. Tie-breaker 2: When list elements are pushed one by one to a stack, the last element in the list will be at the top of the stack.
The GSP stack shown below grows downwards, so the last line is the top of the stack, it shows the first three actions pushed and no other action has been pushed/popped yet, and the plan is currently empty.
Analyze the stack, determine the three actions and then answer the sub-questions.
Determine the proposition(s) in the current state that will trigger the popping of ACTION-3, ACTION-2 and ACTION-1 in that order. Enter those propositions (in sorted order) in the text box.
Enter NIL or enter a comma separated list of propositions in alphabetical order. NO SPACES, TABS OR EXTRANEOUS CHARACTERS.
Answer format: armEmpty,clear(X),holding(X),on(X,Y),onTable(X) Answers Case Sensitive : No