mphantomB1.test

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

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <mrow>
    <mi>A</mi> 
    <mphantom>
      <mi>A</mi> 
    </mphantom> 
    <mi>A</mi> 
    <mo>+</mo> 
    <mfrac>
      <mrow>
        <mn>1</mn> 
        <mo>+</mo> 
        <mn>2</mn> 
        <mo>+</mo> 
        <mn>3</mn> 
      </mrow> 
      <mrow>
        <mn>1</mn> 
        <mo>+</mo> 
        <mphantom>
          <mn>2</mn> 
          <mo form="infix">+</mo> 
        </mphantom> 
        <mn>3</mn> 
      </mrow> 
    </mfrac> 
  </mrow> </math>
>>> native
[ EIdentifier "A"
, EPhantom (EIdentifier "A")
, EIdentifier "A"
, ESymbol Bin "+"
, EFraction
    NormalFrac
    (EGrouped
       [ ENumber "1"
       , ESymbol Bin "+"
       , ENumber "2"
       , ESymbol Bin "+"
       , ENumber "3"
       ])
    (EGrouped
       [ ENumber "1"
       , ESymbol Bin "+"
       , EPhantom (EGrouped [ ENumber "2" , ESymbol Bin "+" ])
       , ENumber "3"
       ])
]