More Examples (negation, union)
SeattleView(buyer,seller,product,store) :-
Person(buyer, “Seattle”, phone),
Purchase(buyer, seller, product, store)
not Purchase(buyer, seller, product, “The Bon”)
Q5(buyer) :- Purchase(buyer, “Joe”, prod, store)
Q5(buyer) :- Purchase(buyer, seller, store, prod),
Product(prod, price, cat, maker)
Company(maker, sp, country),