style>
      <mstyle form="prefix">
        <mrow>
          <mn>1</mn>
          <!-- Infix and prefix forms of − do not have the same lspace/rspace
               values in the operator dictionary -->
          <mo>−</mo>
          <mn>2</mn>
        </mrow>
      </mstyle>
    </math>
    <math displaystyle="true">
      <mstyle>
        <mn>1</mn>
        <mo>A</mo>
        <mn>2</mn>
      </mstyle>
      <mstyle>
        <munder>
          <mo>∑</mo>
          <mn>3</mn>
        </munder>
      