Backwards Chaining: Backwards chaining important assumptions: 1. Rules are tried in the order that they appear 2. Facts are tried in the order that they appear 3. Lazy evaluation rules are in order (ie. if the first part of an AND statement is false, the rest of the AND clause does not need to be evaluated) F1: Mario and Luigi are brothers F2: Mario hits a block F3: Luigi saves Toad F4: Bowser gets away from Luigi F5: Mario is fully grown 1) Using backwards chaining show that Mario saves the princess R1: If ?X and ?Y are brothers Then ?X has a cape R2 IF (?X has a cape AND ?X rides Yoshi ) OR ?X shoots fireballs THEN ?X saves the princess R3: IF ?X saves toad THEN ?X learns the princess is in another castle Gorwards Chaining Make the following assumptions about forward chaining - Rules fire in the order listed - New facts are added to the end of the facts given - If a particular rule matches fact in the list of fact in more than one way, the matches are considered in the order corresponding to how the facts were matched. For example if a particular rule has an antecedent that matches both Fact 1 and Fact 2, then the rule matching fact 1 is considered first Run forward chaining of the list of facts, showing your work in the table. For the first three iterations, fill out the first three rows of the table. In the first column, list all the rules that match during that iteration. In the second column, write down the rule that fires. In the third, write down the fact that is added when the rule is fired. For the rest of the iterations after the 3mat row, simply write down the rule that fires and the fact that is added. You can still write down all the rules that match if it is convenient however only iterations 13 will be graded