Suppose variables x,y denote people. Y(x,y) denotes "x is younger than y". F (x,y) denotes "x is a friend of y". Translate the following sentences into logic: a. Emma is the youngest person b. Ruth is the oldest person c. Everyone has a friend d. There is someone who is everybody's friend. e. There is someone who is nobody's friend. f. Joshua has a younger friend.