rec-lowlimit1

W3C sample WIRIS
x a b f x
<math xmlns="http://www.w3.org/1998/Math/MathML">
  <apply>
    <int/>
    <bvar>
      <ci>x</ci>
    </bvar>
    <lowlimit>
      <ci>a</ci>
    </lowlimit>
    <uplimit>
      <ci>b</ci>
    </uplimit>
    <apply>
      <ci type="fn">f</ci>
      <ci>x</ci>
    </apply>
  </apply>
</math>

Author: MathML 2 Recommendation