rec-sum1

W3C sample	WIRIS
	$x a b f x x x B f x$

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <apply>
    <sum/>
    <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>
  <apply>
    <sum/>
    <bvar>
      <ci>x</ci>
    </bvar>
    <condition>
      <apply>
        <in/>
        <ci>x</ci>
        <ci type="set">B</ci>
      </apply>
    </condition>
    <apply>
      <ci type="fn">f</ci>
      <ci>x</ci>
    </apply>
  </apply>
</math>

Author: MathML 2 Recomendation