Answer: R = A × A.
- A R = ∅
- B R = {(a, a) : a ∈ A}
- C R = A
- D R = A × A
Correct answer: D. R = A × A
Explanation: The universal relation contains every possible ordered pair, so it is all of A × A.
Concept context
Types of relations, equivalence classes, one-one and onto functions, composition, and invertible functions