<<< native
[ ESubsup
    (EIdentifier "A")
    (ESubsup (EIdentifier "C") (ENumber "4") (ENumber "3"))
    (ESubsup (EIdentifier "B") (ENumber "2") (ENumber "1"))
, ESymbol Rel "="
, ESubsup
    (EIdentifier "A")
    (ESubsup
       (EIdentifier "C")
       (ESub (ENumber "4") (EPhantom (EText TextNormal "l")))
       (ENumber "3"))
    (ESubsup
       (EIdentifier "B")
       (ENumber "2")
       (ESuper (ENumber "1") (EPhantom (EText TextNormal "s"))))
]
>>> 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>A</m:t>
        </m:r>
      </m:e>
      <m:sub>
        <m:sSubSup>
          <m:e>
            <m:r>
              <m:t>C</m:t>
            </m:r>
          </m:e>
          <m:sub>
            <m:r>
              <m:t>4</m:t>
            </m:r>
          </m:sub>
          <m:sup>
            <m:r>
              <m:t>3</m:t>
            </m:r>
          </m:sup>
        </m:sSubSup>
      </m:sub>
      <m:sup>
        <m:sSubSup>
          <m:e>
            <m:r>
              <m:t>B</m:t>
            </m:r>
          </m:e>
          <m:sub>
            <m:r>
              <m:t>2</m:t>
            </m:r>
          </m:sub>
          <m:sup>
            <m:r>
              <m:t>1</m:t>
            </m:r>
          </m:sup>
        </m:sSubSup>
      </m:sup>
    </m:sSubSup>
    <m:r>
      <m:rPr>
        <m:sty m:val="p" />
      </m:rPr>
      <m:t>=</m:t>
    </m:r>
    <m:sSubSup>
      <m:e>
        <m:r>
          <m:t>A</m:t>
        </m:r>
      </m:e>
      <m:sub>
        <m:sSubSup>
          <m:e>
            <m:r>
              <m:t>C</m:t>
            </m:r>
          </m:e>
          <m:sub>
            <m:sSub>
              <m:e>
                <m:r>
                  <m:t>4</m:t>
                </m:r>
              </m:e>
              <m:sub>
                <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>l</m:t>
                    </m:r>
                  </m:e>
                </m:phant>
              </m:sub>
            </m:sSub>
          </m:sub>
          <m:sup>
            <m:r>
              <m:t>3</m:t>
            </m:r>
          </m:sup>
        </m:sSubSup>
      </m:sub>
      <m:sup>
        <m:sSubSup>
          <m:e>
            <m:r>
              <m:t>B</m:t>
            </m:r>
          </m:e>
          <m:sub>
            <m:r>
              <m:t>2</m:t>
            </m:r>
          </m:sub>
          <m:sup>
            <m:sSup>
              <m:e>
                <m:r>
                  <m:t>1</m:t>
                </m:r>
              </m:e>
              <m:sup>
                <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>s</m:t>
                    </m:r>
                  </m:e>
                </m:phant>
              </m:sup>
            </m:sSup>
          </m:sup>
        </m:sSubSup>
      </m:sup>
    </m:sSubSup>
  </m:oMath>
</m:oMathPara>