Give an example of a relation. Which is

Symmetric and transitive but not reflexive.


Let A = {-7, -8}

Define a relation R on A as:


R = {(-7, -8), (-8, -7), (-7, -7)}


Relation R is not reflexive as (-8, -8) R


Relation R is symmetric as (-7, -8) ϵ R and (-8, -7) ϵ R


But it is seen that (-7, -8), (-8, -7) ϵ R.


Also, (-7, -7) ϵ R.


R is transitive.


Therefore, relation R is symmetric and transitive but not reflexive.


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