Give examples of relation which are
(i) Neither reflexive nor symmetric nor transitive.
(ii) symmetric and reflexive but not transitive.
(iii) Reflexive and transitive but not symmetric.
Let A = {1, 2, 3}
(i) R = {(1, 1), (2, 3), (3, 1)}
(ii) R = {(1, 1), (2, 2), (3, 3), (1, 2), (2, 1), (2, 3), (3, 2)}
(iii) R = {(1, 1), (2, 2), (3, 3), (1, 2)}
Note: - To avoid reflexivity, one of (x, x) should be kept outside of R. To avoid symmetry, take (x, y) ∈R with (y, x) ∉ R. To avoid transitivity, take two pairs (x, y) R and (y , z) ∈ R such that (x, z) ∉ R.