<<< native
[ EArray
    [ AlignCenter , AlignCenter ]
    [ [ [ EText TextNormal "single integral" ]
      , [ EGrouped
            [ EGrouped [ ESymbol Op "\8747" , EIdentifier "x" ]
            , EGrouped [ ESymbol Op "\8747" , EIdentifier "M" ]
            , EDelimited
                "\8747"
                ""
                [ Right (EFraction NormalFrac (EIdentifier "x") (EIdentifier "o"))
                ]
            , EDelimited
                "\8747"
                ""
                [ Right (EFraction NormalFrac (EIdentifier "A") (EIdentifier "o"))
                ]
            , EDelimited
                "\8747"
                ""
                [ Right (EFraction NormalFrac (EIdentifier "x") (EIdentifier "A"))
                ]
            , EDelimited
                "\8747"
                ""
                [ Right (EFraction NormalFrac (EIdentifier "A") (EIdentifier "M"))
                ]
            , EDelimited
                "\8747"
                ""
                [ Right (EFraction NormalFrac (EIdentifier ".") (EIdentifier "''"))
                ]
            ]
        ]
      ]
    , [ [ EText TextNormal "double integral" ]
      , [ EGrouped
            [ EDelimited
                "\8747"
                ""
                [ Right (EDelimited "\8747" "" [ Right (EIdentifier "x") ]) ]
            , EDelimited
                "\8747"
                ""
                [ Right (EDelimited "\8747" "" [ Right (EIdentifier "M") ]) ]
            , EDelimited
                "\8747"
                ""
                [ Right
                    (EDelimited
                       "\8747"
                       ""
                       [ Right (EFraction NormalFrac (EIdentifier "x") (EIdentifier "o"))
                       ])
                ]
            , EDelimited
                "\8747"
                ""
                [ Right
                    (EDelimited
                       "\8747"
                       ""
                       [ Right (EFraction NormalFrac (EIdentifier "A") (EIdentifier "o"))
                       ])
                ]
            , EDelimited
                "\8747"
                ""
                [ Right
                    (EDelimited
                       "\8747"
                       ""
                       [ Right (EFraction NormalFrac (EIdentifier "x") (EIdentifier "A"))
                       ])
                ]
            , EDelimited
                "\8747"
                ""
                [ Right
                    (EDelimited
                       "\8747"
                       ""
                       [ Right (EFraction NormalFrac (EIdentifier "A") (EIdentifier "M"))
                       ])
                ]
            , EDelimited
                "\8747"
                ""
                [ Right
                    (EDelimited
                       "\8747"
                       ""
                       [ Right (EFraction NormalFrac (EIdentifier ".") (EIdentifier "''"))
                       ])
                ]
            ]
        ]
      ]
    , [ [ EText TextNormal "double nested integral" ]
      , [ EGrouped
            [ EDelimited
                "\8747"
                ""
                [ Right (EDelimited "\8747" "" [ Right (EIdentifier "x") ]) ]
            , EDelimited
                "\8747"
                ""
                [ Right (EDelimited "\8747" "" [ Right (EIdentifier "M") ]) ]
            , EDelimited
                "\8747"
                ""
                [ Right
                    (EDelimited
                       "\8747"
                       ""
                       [ Right (EFraction NormalFrac (EIdentifier "x") (EIdentifier "o"))
                       ])
                ]
            , EDelimited
                "\8747"
                ""
                [ Right
                    (EDelimited
                       "\8747"
                       ""
                       [ Right (EFraction NormalFrac (EIdentifier "A") (EIdentifier "o"))
                       ])
                ]
            , EDelimited
                "\8747"
                ""
                [ Right
                    (EDelimited
                       "\8747"
                       ""
                       [ Right (EFraction NormalFrac (EIdentifier "x") (EIdentifier "A"))
                       ])
                ]
            , EDelimited
                "\8747"
                ""
                [ Right
                    (EDelimited
                       "\8747"
                       ""
                       [ Right (EFraction NormalFrac (EIdentifier "A") (EIdentifier "M"))
                       ])
                ]
            , EDelimited
                "\8747"
                ""
                [ Right
                    (EDelimited
                       "\8747"
                       ""
                       [ Right (EFraction NormalFrac (EIdentifier ".") (EIdentifier "''"))
                       ])
                ]
            ]
        ]
      ]
    ]
]
>>> mml
<?xml version='1.0' ?>
<math display="block" xmlns="http://www.w3.org/1998/Math/MathML">
  <mtable>
    <mtr>
      <mtd columnalign="center" style="text-align: center">
        <mtext mathvariant="normal">single integral</mtext>
      </mtd>
      <mtd columnalign="center" style="text-align: center">
        <mrow>
          <mrow>
            <mo>∫</mo>
            <mi>x</mi>
          </mrow>
          <mrow>
            <mo>∫</mo>
            <mi>M</mi>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mfrac>
              <mi>x</mi>
              <mi>o</mi>
            </mfrac>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mfrac>
              <mi>A</mi>
              <mi>o</mi>
            </mfrac>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mfrac>
              <mi>x</mi>
              <mi>A</mi>
            </mfrac>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mfrac>
              <mi>A</mi>
              <mi>M</mi>
            </mfrac>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mfrac>
              <mi>.</mi>
              <mi>&#39;&#39;</mi>
            </mfrac>
          </mrow>
        </mrow>
      </mtd>
    </mtr>
    <mtr>
      <mtd columnalign="center" style="text-align: center">
        <mtext mathvariant="normal">double integral</mtext>
      </mtd>
      <mtd columnalign="center" style="text-align: center">
        <mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mrow>
              <mo stretchy="true" form="prefix">∫</mo>
              <mi>x</mi>
            </mrow>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mrow>
              <mo stretchy="true" form="prefix">∫</mo>
              <mi>M</mi>
            </mrow>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mrow>
              <mo stretchy="true" form="prefix">∫</mo>
              <mfrac>
                <mi>x</mi>
                <mi>o</mi>
              </mfrac>
            </mrow>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mrow>
              <mo stretchy="true" form="prefix">∫</mo>
              <mfrac>
                <mi>A</mi>
                <mi>o</mi>
              </mfrac>
            </mrow>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mrow>
              <mo stretchy="true" form="prefix">∫</mo>
              <mfrac>
                <mi>x</mi>
                <mi>A</mi>
              </mfrac>
            </mrow>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mrow>
              <mo stretchy="true" form="prefix">∫</mo>
              <mfrac>
                <mi>A</mi>
                <mi>M</mi>
              </mfrac>
            </mrow>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mrow>
              <mo stretchy="true" form="prefix">∫</mo>
              <mfrac>
                <mi>.</mi>
                <mi>&#39;&#39;</mi>
              </mfrac>
            </mrow>
          </mrow>
        </mrow>
      </mtd>
    </mtr>
    <mtr>
      <mtd columnalign="center" style="text-align: center">
        <mtext mathvariant="normal">double nested integral</mtext>
      </mtd>
      <mtd columnalign="center" style="text-align: center">
        <mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mrow>
              <mo stretchy="true" form="prefix">∫</mo>
              <mi>x</mi>
            </mrow>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mrow>
              <mo stretchy="true" form="prefix">∫</mo>
              <mi>M</mi>
            </mrow>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mrow>
              <mo stretchy="true" form="prefix">∫</mo>
              <mfrac>
                <mi>x</mi>
                <mi>o</mi>
              </mfrac>
            </mrow>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mrow>
              <mo stretchy="true" form="prefix">∫</mo>
              <mfrac>
                <mi>A</mi>
                <mi>o</mi>
              </mfrac>
            </mrow>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mrow>
              <mo stretchy="true" form="prefix">∫</mo>
              <mfrac>
                <mi>x</mi>
                <mi>A</mi>
              </mfrac>
            </mrow>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mrow>
              <mo stretchy="true" form="prefix">∫</mo>
              <mfrac>
                <mi>A</mi>
                <mi>M</mi>
              </mfrac>
            </mrow>
          </mrow>
          <mrow>
            <mo stretchy="true" form="prefix">∫</mo>
            <mrow>
              <mo stretchy="true" form="prefix">∫</mo>
              <mfrac>
                <mi>.</mi>
                <mi>&#39;&#39;</mi>
              </mfrac>
            </mrow>
          </mrow>
        </mrow>
      </mtd>
    </mtr>
  </mtable>
</math>