Graph of a function

The graph is a subset of the Cartesian product and consists of ordered pairs. Viewing a function as a special kind of relation, the graph is exactly the corresponding relation.

• If $f:\mathbb R\to\mathbb R$ is $f(x)=x^2$, then $\Gamma_f=\{(x,x^2):x\in\mathbb R\}$.
• If $A$ is any set, the graph of $\mathrm{id}_A$ is $\{(a,a):a\in A\}$.