The correct answer is: Both Repeated states & Incompleteness.
Backward chaining is a search technique used in artificial intelligence (AI) search. It is a top-down approach, where the goal is to find a solution to a problem by starting with the goal and working backwards through the problem space.
Backward chaining can be used to solve a variety of problems, including planning, scheduling, and diagnosis. It is a powerful technique, but it can also be difficult to implement correctly.
One of the challenges of backward chaining is that it can lead to repeated states. This is because the algorithm may need to explore the same state multiple times in order to find a solution. This can be inefficient, and it can also make it difficult to debug the algorithm.
Another challenge of backward chaining is that it can be incomplete. This is because the algorithm may not be able to find a solution if there is no solution to the problem. This can be a problem if the goal is to find a solution to a problem, rather than just to prove that there is no solution.
Despite these challenges, backward chaining is a powerful technique that can be used to solve a variety of problems. It is important to be aware of the challenges of backward chaining, but it is also important to remember that it is a powerful tool that can be used to solve difficult problems.
Here is a more detailed explanation of each option:
- Repeated states can occur in backward chaining when the algorithm needs to explore the same state multiple times in order to find a solution. This can be inefficient, and it can also make it difficult to debug the algorithm.
- Incompleteness can occur in backward chaining when the algorithm is not able to find a solution if there is no solution to the problem. This can be a problem if the goal is to find a solution to a problem, rather than just to prove that there is no solution.
- Complexity can occur in backward chaining because it is a recursive algorithm. This means that the algorithm calls itself, which can lead to a stack overflow if the problem is too complex.
In conclusion, the correct answer is: Both Repeated states & Incompleteness.