<?xml version="1.0" encoding="UTF-8"?>

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <mn>
    <mglyph fontfamily="Arial" index="97" alt="lowercase 'a'"></mglyph> 
  </mn> 
  <mspace width="10px"></mspace> 
  <mi>
    <mglyph fontfamily="Arial" index="105"></mglyph> 
  </mi> 
  <mspace width="10px"></mspace> 
  <mn>
    <mglyph fontfamily="fake-font" index="105"></mglyph> 
  </mn> 
  <mspace width="10px"></mspace> 
  <mi>
    <mglyph index="97" alt="lowercase 'a'"></mglyph> 
  </mi> 
</math>