texmath-0.12.5: test/writer/mml/msub-08.test

<<< native
[ ESub (EIdentifier "A") (ESub (EIdentifier "B") (EIdentifier "C"))
, ESymbol Rel "="
, ESub
    (EIdentifier "A")
    (ESub
       (EIdentifier "B")
       (EUnder False (EIdentifier "C") (EPhantom (EIdentifier "D"))))
]
>>> mml
<?xml version='1.0' ?>
<math display="block" xmlns="http://www.w3.org/1998/Math/MathML">
  <mrow>
    <msub>
      <mi>A</mi>
      <msub>
        <mi>B</mi>
        <mi>C</mi>
      </msub>
    </msub>
    <mo>=</mo>
    <msub>
      <mi>A</mi>
      <msub>
        <mi>B</mi>
        <munder>
          <mi>C</mi>
          <mphantom>
            <mi>D</mi>
          </mphantom>
        </munder>
      </msub>
    </msub>
  </mrow>
</math>