Display:

$b\mapsto \int_a^b f(x)\,d x$

Source:

<lambda>
     <bvar>
          <ci> b </ci>
     </bvar>
     <apply>
          <int/>
          <bvar>
               <ci> x </ci>
          </bvar>
          <lowlimit>
               <ci> a </ci>
          </lowlimit>
          <uplimit>
               <ci> b </ci>
          </uplimit>
          <apply>
               <fn>
                    <ci> f </ci>
               </fn>
               <ci> x </ci>
          </apply>
     </apply>
</lambda>