Indicator function

Let $X$ be a D11: Set.
The indicator function on $X$ with respect to $E \subseteq X$ is the D992: Function $$X \to \{ 0, 1 \}, \quad x \mapsto \begin{cases} 1, \quad & x \in E \\ 0, \quad & x \in X \setminus E \end{cases}$$
Conventions
Convention 0 (Notation for indicator function) : Let $X$ be a D11: Set. We denote the D41: Indicator function on $X$ with respect to $E \subseteq X$ by $I_E$.
Subdefinitions
Child definitions
Results