rec-partialdiff3

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <apply>
    <apply>
      <csymbol cd="calculus1">partialdiffdegree</csymbol>
      <apply>
        <csymbol cd="list1">list</csymbol>
        <ci>m</ci>
        <ci>n</ci>
      </apply>
      <ci>k</ci>
      <bind>
        <csymbol cd="fns1">lambda</csymbol>
        <bvar>
          <ci>x</ci>
        </bvar>
        <bvar>
          <ci>y</ci>
        </bvar>
        <apply>
          <semantics>
            <ci>f</ci>
            <annotation-xml cd="mathmltypes" name="type" encoding="MathML-Content">
              <ci>fn</ci>
            </annotation-xml>
          </semantics>
          <ci>x</ci>
          <ci>y</ci>
        </apply>
      </bind>
    </apply>
    <ci>x</ci>
    <ci>y</ci>
  </apply>
</math>

Author: MathML 2 Recommendation