Question

Let the domain for x be the set of all students in this class and the domain for y be the set of all
countries in the world. Let P(x; y) denote "student x has visited country y" and Q(x; y) denote
"student x has a friend in country y." Express each of the following using logical operations and
quantiers, and the propositional functions P(x; y) and Q(x; y).

(a) Carlos has visited Bulgaria.
(b) Every student in this class has visited the United States.
(c) Every student in this class has visited some country in the world.