Display:

x a b f x x x B f x

Source:


<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>