Inference in First-Order Logic
Consider the following statements in English.
If a girl is cute, some boys will love her. If a girl is poor, no boys will love her.
Assume that you are given the following predicates:
• Girl(X) — X is a girl.
• Boy(X)— X is a boy.
• Poor(X)—X is poor.
• Cute(X) —X is cute.
• Loves(X, Y ) —X will love Y .
(a) Translate the two statements above into first-order logic using these predicates.
(b) Convert the two sentences in part (a) into clausal form.
(c) Prove using resolution by refutation that All poor girls are not cute. Show
any unifiers required for the resolution. Be sure to provide a clear numbering of the
sentences in the knowledge base and indicate which sentences are involved in each
step of the proof.
