title: What is wrong with my MathJax square bracket syntax?
body: <p>This mathjax expression (in an asciidoctor document in a VS Code preview using <a href="https://github.com/asciidoctor/asciidoctor-vscode" rel="nofollow noreferrer">asciidoctor-vscode</a>) fails to render correctly:</p>
  <pre><code>stem:[  = x_l = x_( ([m]+1) /2)   ]
  </code></pre>
  <p>The ] after the m acts like a ) for the _, and ends it early. How can I force the parser to understand my brackets please?</p>