<p>
      <math xmlns="http://www.w3.org/1998/Math/MathML">
        <mrow>
          <mo>{</mo>
          <mi>x</mi>
          <mspace width="2mm" height="2mm" />
          <mo stretchy="false">|</mo>
          <mspace width="2mm" height="2mm" />
          <mi>x</mi>
          <mspace width="2mm" height="2mm" />
          <mi>is</mi>
          <mspace width="2mm" height="2mm" />
          <mi>an</mi>
          <mspace width="2mm" height="2mm" />
          <mi>even</mi>
          <mspace width="2mm" height="2mm" />
          <mi>integer</mi>
          <mspace width="2mm" height="2mm" />
          <mi>number</mi>
          <mo>}</mo>
        </mrow>
      </math>
    </p>

    <p>
      <math xmlns="http://www.w3.org/1998/Math/MathML">
        <mo stretchy="false">{</mo>
        <mi>x</mi>
        <mspace width="2mm" height="2mm" />
        <mo stretchy="false">|</mo>
        <mspace width="2mm" height="2mm" />
        <mi>x</mi>
      </math> is an even integer number<math
       xmlns="http://www.w3.org/1998/Math/MathML">
         <mo stretchy="false">}</mo></math>
    </p>