Understanding Prolog: Facts, Rules, Queries

What is a fact in Prolog?

• A statement that defines a condition that must be true.

• A statement that is always true and represents basic assertions about the world.

• A statement that defines a relationship between two or more facts.

• A statement that asks a question about the facts and rules.

Which of the following is an example of a Prolog fact?

• `likes(john, pizza).`

• `likes(X, Y) :- loves(X, Y).`

• `?- likes(john, pizza).`

• `if likes(john, pizza) then true.`

What is a rule in Prolog?

• A statement that is always true and represents basic assertions about the world.

• A statement that defines a relationship between facts and can be used to infer new information.

• A statement that asks a question about the facts and rules.

• A statement that defines a condition that must be true.

Which of the following is an example of a Prolog rule?

• `likes(john, pizza).`

• `likes(X, Y) :- loves(X, Y).`

• `?- likes(john, pizza).`

• `if likes(john, pizza) then true.`

What is a query in Prolog?

• A statement that is always true and represents basic assertions about the world.

• A statement that defines a relationship between facts and can be used to infer new information.

• A statement that asks a question about the facts and rules.

• A statement that defines a condition that must be true.

Which of the following is an example of a Prolog query?

• `likes(john, pizza).`

• `likes(X, Y) :- loves(X, Y).`

• `?- likes(john, pizza).`

• `if likes(john, pizza) then true.`

In Prolog, how would you express that "John likes anyone who loves pizza"?

• `likes(john, X) :- loves(X, pizza).`

• `loves(john, X) :- likes(X, pizza).`

• `likes(X, john) :- loves(pizza, X).`

• `loves(X, pizza) :- likes(john, X).`

What does the following Prolog rule mean: `happy(X) :- rich(X), healthy(X).`?

• X is happy if X is rich or healthy.

• X is happy if X is rich and healthy.

• X is happy if X is not rich and healthy.

• X is happy if X is neither rich nor healthy.

Which of the following statements is true about Prolog facts?

• Facts can contain variables.

• Facts are used to define conditions.

• Facts are always true and do not contain variables.

• Facts are used to ask questions.

How would you represent the fact "Mary is a student" in Prolog?

• `student(mary).`

• `is_student(mary).`

• `mary(student).`

• `student_of(mary).`