Sort - Less than Operator

less than is a comparison operator that creates a binary relationship.

The relation less than or equal to (<=) on the set of integers {1, 2, 3} is the following set of tuple

<1, 1>, 
<1, 2>, 
<1, 3>, 
<2, 2>, 
<2, 3>, 
<3, 3>

The relationship less than or equal between y and x (ie y <= x) can be represented in the set <math>R</math> against <math>R^2</math> as the below gray area: