To analyze the relation R = {(a, a)} on set A, we need to understand the definitions of symmetric and antisymmetric relations.
Symmetric Relation
A relation R is symmetric if, for every pair (x, y) in R, the pair (y, x) is also in R. In this case, since R contains only the pair (a, a), we have:
- (a, a) implies (a, a) is also in R.
This means R is symmetric.
Antisymmetric Relation
A relation R is antisymmetric if, for every pair (x, y) in R, whenever (x, y) and (y, x) are both in R, then x must equal y. Here, we only have the pair (a, a), which satisfies this condition because:
- Since (a, a) is in R, and (a, a) implies a = a, R is antisymmetric.
Final Assessment
Given that R is both symmetric and antisymmetric, the correct answer is:
3) Symmetric and antisymmetric