Q:

Latex words within eqnarray are getting emphasized

I have a latex equation within an eqnarray as follows, 
\begin{eqnarray*}\nonumber
f(\xi) = \min \xi\\
where, \forall n_{j} \in N, \xi = \max (\xi_{1}, \xi_{2}, .., \xi_{j})\\
s.t.\\
\forall n_{j} \in N, \sum_{C_{i} \in C} x_{ij} \leq \eta_{j}\\
\end{eqnarray*}

But the problem is that the word "where" is getting emphasized which I do not want. The word max is not getting emphasized as it is reserved word preceded by a "\". 
Is there any way I can deemphasize the word "where"? The same is the fate of the letters "s.t." - I also don't want them emphasized inside the eqnarray.

A:

It is not that "where" is getting emphasized; rather, it is being typeset as if it were a term in an equation, i.e. w*h*e*r*e.  Write \mbox{where,} instead (or \text{where,} with amsmath).  And you should do the same with s.t. on the next line.

