<p>I'm new to the field of statistics. While reading a book, I came across some symbols or code-like text (shown below) which I was not able to interpret. I tried Google, but it couldn't help either. I remember seeing similar text in this site and so I'm posting this question here. What is this text and how to read this? Please give some pointers to understand this kind of text.</p>

<pre><code>\begin{eqnarray} 
\mbox{output} &amp; = &amp; \left\{ 
\begin{array}{ll} 
0 &amp; \mbox{if } \sum_j w_j x_j \leq \mbox{ threshold} \\ 
1 &amp; \mbox{if } \sum_j w_j x_j &gt; \mbox{ threshold} 
\end{array} \right. \tag{1}
\end{eqnarray}
</code></pre>

<p>Please feel free to edit the question or move it the right place if this is not the right place to ask.</p>
