I need to make an equation case with text following it. That text should be displayed in the middle of the two cases. This is my code:
\begin{eqnarray}\label{eq13}
a_k =
\begin{cases}
1 & \text{if $f_i$ has a value $v_k$}, \\
0 & \text{otherwise}
\end{cases}
\text{$f_i$ is a non-binary feature, \\$k=1,...,n$}
\end{eqnarray}
It wouldn't work, I want to begin a new line with $k=1,...,n$
, since it sticks out of the page. I am using ACM format. How can I solve the problem?