- \(\mathbf{1}_A\) is the
**indicator function on the set**\(A\). It is defined by \[ \mathbf{1}_A(x) = \begin{cases} 1 & \text{if $x \in A$}\\ 0 & \text{if $x \not \in A$} \end{cases}\]

Learning probability by doing !

- \(\mathbf{1}_A\) is the
**indicator function on the set**\(A\). It is defined by \[ \mathbf{1}_A(x) = \begin{cases} 1 & \text{if $x \in A$}\\ 0 & \text{if $x \not \in A$} \end{cases}\]