= 6 Example 23 Let A = {1, 2, 3} Then show that  the number of relations containing (1, 2)
and (2, 3) which are reflexive and transitive but not symmetric is three Solution The smallest relation R1 containing (1, 2) and (2, 3) which is reflexive and
transitive but not symmetric is {(1, 1), (2, 2), (3, 3), (1, 2), (2, 3), (1, 3)}