title: How can I get non-italic greek characters in a title/label (matplotlib)
body: <p>I am trying to get non-italic greek characters into my matplotlib titles and labels, for example μ. I have so far written greek characters as follows:</p>
  
  <pre><code>plt.title('$\mu$)
  </code></pre>
  
  <p>This would print an italic mu. Now hoping to get it to be non-italic, I have tried to do:</p>
  
  <pre><code>plt.title('$\mathrm{\mu}$')
  </code></pre>
  
  <p>Sadly this does not change it at all, even though using \mathrm does work for normal characters. For example <code>plt.title('$\mathrm{test}$')</code> correctly prints 'test' in a non-italic font.</p>
  
  <p>Why is this behaviour different for greek characters, and how do I fix this? I have googled and found more questions on this problem, but I couldn't get a clear answer on why \mathrm does not work and how I can solve this.</p>
  
  <p>Thanks in advance!</p>