Set Theory – Is an Anti-Symmetric Relation Also Reflexive?

elementary-set-theoryrelations

According to the definition of an Anti-Symmetric Relation if xRy and yRx then x = y

Which means, effectively, x is in relation with itself. Does this mean that anti-symmetry implies reflexive property as well?

Best Answer

Your definition is wrong. The relation $R$ is antisymmetric if, whenever $x\mathrel{R}y$ and $y\mathrel R x$ it holds that $x=y$.

An example of a relation that is antisymmetric but not reflexive is $>$ on the set of integers.

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