We say that x is related to y by R, written x R y, if, and only if, (x, y) ∈ R. Denoted as x R y ⇔ (x, y) ∈ R . Set of all functions is a proper subset of the set of all relations. A relation L : R → R as follows. For all real numbers x and y, (x, y) ∈ L ⇔ x L y ⇔ x < y. Draw the graph of L as a subset of the Cartesian plane R × R.