<<< native
[ EUnderover
    False
    (EIdentifier "_ baseline _")
    (EIdentifier "under script")
    (EPhantom (EIdentifier "fail"))
, ESymbol Rel "="
, EUnder
    False (EIdentifier "_ baseline _") (EIdentifier "under script")
]
>>> omml
<?xml version='1.0' ?>
<m:oMathPara>
  <m:oMathParaPr>
    <m:jc m:val="center" />
  </m:oMathParaPr>
  <m:oMath>
    <m:limLow>
      <m:e>
        <m:limUpp>
          <m:e>
            <m:r>
              <m:t>_ baseline _</m:t>
            </m:r>
          </m:e>
          <m:lim>
            <m:phant>
              <m:phantPr>
                <m:show m:val="0" />
              </m:phantPr>
              <m:e>
                <m:r>
                  <m:t>fail</m:t>
                </m:r>
              </m:e>
            </m:phant>
          </m:lim>
        </m:limUpp>
      </m:e>
      <m:lim>
        <m:r>
          <m:t>under script</m:t>
        </m:r>
      </m:lim>
    </m:limLow>
    <m:r>
      <m:rPr>
        <m:sty m:val="p" />
      </m:rPr>
      <m:t>=</m:t>
    </m:r>
    <m:limLow>
      <m:e>
        <m:r>
          <m:t>_ baseline _</m:t>
        </m:r>
      </m:e>
      <m:lim>
        <m:r>
          <m:t>under script</m:t>
        </m:r>
      </m:lim>
    </m:limLow>
  </m:oMath>
</m:oMathPara>