<<< native
[ ESubsup (EIdentifier "T") (EIdentifier "m") (EIdentifier "n")
, ESymbol Rel "="
, EOver
    False
    (ESubsup (EIdentifier "T") (EIdentifier "m") (EIdentifier "n"))
    (EPhantom (EText TextNormal "x"))
]
>>> omml
<?xml version='1.0' ?>
<m:oMathPara>
  <m:oMathParaPr>
    <m:jc m:val="center" />
  </m:oMathParaPr>
  <m:oMath>
    <m:sSubSup>
      <m:e>
        <m:r>
          <m:t>T</m:t>
        </m:r>
      </m:e>
      <m:sub>
        <m:r>
          <m:t>m</m:t>
        </m:r>
      </m:sub>
      <m:sup>
        <m:r>
          <m:t>n</m:t>
        </m:r>
      </m:sup>
    </m:sSubSup>
    <m:r>
      <m:rPr>
        <m:sty m:val="p" />
      </m:rPr>
      <m:t>=</m:t>
    </m:r>
    <m:limUpp>
      <m:e>
        <m:sSubSup>
          <m:e>
            <m:r>
              <m:t>T</m:t>
            </m:r>
          </m:e>
          <m:sub>
            <m:r>
              <m:t>m</m:t>
            </m:r>
          </m:sub>
          <m:sup>
            <m:r>
              <m:t>n</m:t>
            </m:r>
          </m:sup>
        </m:sSubSup>
      </m:e>
      <m:lim>
        <m:phant>
          <m:phantPr>
            <m:show m:val="0" />
          </m:phantPr>
          <m:e>
            <m:r>
              <m:rPr>
                <m:nor />
                <m:sty m:val="p" />
              </m:rPr>
              <m:t>x</m:t>
            </m:r>
          </m:e>
        </m:phant>
      </m:lim>
    </m:limUpp>
  </m:oMath>
</m:oMathPara>