ithin base.
            The msqrt element leaves both attributes unchanged within its
            argument. -->
    <math>
      <mstyle displaystyle="true">
        <mroot>
          <munder><mo>O</mo><mo>O</mo></munder>
          <msub><mo>O</mo><mo>O</mo></msub>
        </mroot>
        <msqrt>
          <munder><mo>O</mo><mo>O</mo></munder>
        </msqrt>
      </mstyle>
    </math>

<!--
    The msub element [...] increments scriptlevel by 1, and sets displaystyle to
   "false", within subscript, but