<<< native
[ EArray
    [ AlignCenter ]
    [ [ [ EArray [ AlignCenter ] [ [ [ EIdentifier "x" ] ] ] ] ] ]
]
>>> omml
<?xml version='1.0' ?>
<m:oMathPara>
  <m:oMathParaPr>
    <m:jc m:val="center" />
  </m:oMathParaPr>
  <m:oMath>
    <m:m>
      <m:mPr>
        <m:baseJc m:val="center" />
        <m:plcHide m:val="1" />
        <m:mcs>
          <m:mc>
            <m:mcPr>
              <m:mcJc m:val="center" />
              <m:count m:val="1" />
            </m:mcPr>
          </m:mc>
        </m:mcs>
      </m:mPr>
      <m:mr>
        <m:e>
          <m:m>
            <m:mPr>
              <m:baseJc m:val="center" />
              <m:plcHide m:val="1" />
              <m:mcs>
                <m:mc>
                  <m:mcPr>
                    <m:mcJc m:val="center" />
                    <m:count m:val="1" />
                  </m:mcPr>
                </m:mc>
              </m:mcs>
            </m:mPr>
            <m:mr>
              <m:e>
                <m:r>
                  <m:t>x</m:t>
                </m:r>
              </m:e>
            </m:mr>
          </m:m>
        </m:e>
      </m:mr>
    </m:m>
  </m:oMath>
</m:oMathPara>