For any $i$ and $j$, we write
\[\delta_{i, j} = \begin{cases} 1, & \text{if $i = j$}, \\ 0, & \text{if $i \neq j$}, \end{cases}\]Using Iverson Brackets we have
\[\delta_{i, j} = [i = j].\]
For any $i$ and $j$, we write
\[\delta_{i, j} = \begin{cases} 1, & \text{if $i = j$}, \\ 0, & \text{if $i \neq j$}, \end{cases}\]Using Iverson Brackets we have
\[\delta_{i, j} = [i = j].\]