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Prove that the following relation is an order on the Cartesian product {${1,2,3}$} × {${1,2,3}$} and draw its diagram.

$((x_1,x_2),(y_1,y_2))$ER if and only if $x_1 < x_2$ or $x_1=x_2$ and $y_1 ≤ y_2$

I can prove that this is reflexive, but I don't know how to prove it for anti-symmetricity and transivity.

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    For future reference, this is known as the *lexicographical order*.2012-11-12
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    It is about 9 elements. Write them down all, preferaribly according to the given order, you can also skip the parenthesis and the comma, so that the elements of the cartesian product may now be written like: 11, 32, 13, 22, ... maybe that helps.2012-11-12

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