MODULE      Sports.

IMPORT      Sets.

BASE        Person, Sport, PersonSports.

CONSTANT    Mary, Bill, Joe, Fred : Person;
            Cricket, Football, Tennis : Sport.

FUNCTION    Pair : Person * Set(Sport) -> PersonSports.

PREDICATE   Likes : Person * Sport.

Likes(Mary, Cricket).
Likes(Mary, Tennis).
Likes(Bill, Cricket).
Likes(Bill, Tennis).
Likes(Joe, Tennis).
Likes(Joe, Football).
