Backward Chaining and Prolog

CSC 261 - Artificial Intelligence - Weinman

1. Chapter 7 introduced chaining-based inference algorithms for propositional logic. The prior (second) edition of the text concluded section 7.5.4 with the statement that

   an agent should share the work between forward and backward reasoning, limiting forward reasoning to the generation of facts that are likely to be relevant to queries that will be solved by backward chaining. (Russell & Norvig 2003, p. 220)

   Select the sentence from today's reading that you feel best supports this claim. Briefly explain why you chose this sentence.
2. In your own words, explain the purpose of the (antepenultimate) line of FOL-BC-ASK, which reads,
   for each θ' in FOL-BC-OR(KB, SUBST(θ,first),θ) do
3. In your own words, explain what a Prolog rule is and why it is useful.
4. Select the sentence from today's reading that you feel best illustrates the power of recursive rules. Briefly explain why you chose this sentence.
5. Select the sentence from today's reading that you feel best illustrates the danger of recursive rules. Briefly explain why you chose this sentence.