# Is the relation {(1, 3) (2, 4)} a function?

Since $\left(x , y\right) = \left\{\begin{matrix}1 & 3 \\ 2 & 4\end{matrix}\right\}$ provides a unique mapping for any value of $x$ into a value of $y$ (that is the values of $x$ are not duplicated in the pairs of the set)
$\textcolor{w h i t e}{\text{XXXX}}$this is a function.