If R is a binary relation in a set X ≠∅ that is symmetric, transitive, then R is reflexive.
This is false and I have to change the argument to make it true. How can I do this? Thanks!
If R is a binary relation in a set X ≠∅ that is symmetric, transitive, then R is reflexive.
This is false and I have to change the argument to make it true. How can I do this? Thanks!
If for every $x\in X$ there is some $y\in X$ such that $xRy$, then $yRx$ because $R$ is symmetric. Then, $xRy$ and $yRx$, so $xRx$ since $R$· is transitive.
But the condition "for every $x\in X$ there is some $y\in X$ such that $xRy$" is essential.