The ReLU function is the D4367: Unsigned real function
\begin{equation}
\mathbb{R} \to [0, \infty), \quad
x \mapsto x I_{[0, \infty)}(x)
\end{equation}
The ReLU function is the D4367: Unsigned real function
\begin{equation}
\mathbb{R} \to [0, \infty), \quad
x \mapsto x I_{x \in [0, \infty)}
\end{equation}
