Answer: (a, b) ∈ R implies (b, a) ∈ R.
- A (a, b) ∈ R implies a = b
- B (a, b) ∈ R implies (b, a) ∈ R
- C (a, a) ∈ R for all a
- D R contains every ordered pair
Correct answer: B. (a, b) ∈ R implies (b, a) ∈ R
Explanation: Symmetry means the relation holds in both directions whenever it holds at all.
Concept context
Types of relations, equivalence classes, one-one and onto functions, composition, and invertible functions