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Question
Prove that the relation “friendship” is not an equivalence relation on the set of all people in Chennai
Solution
(a) S = aRa
(i.e.) a person can be a friend to himself or herself.
So it is reflective.
(b) aRb ⇒ bRa so it is symmetric
(c) aRb, bRc does not
⇒ aRc so it is not transitive
⇒ It is not an equivalence relation
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