<OMOBJ xmlns="http://www.openmath.org/OpenMath">
<OMA><OMS cd="relation1" name="eq"/>
<OMA><OMS cd="weylalgebra1" name="act"/>
<OMA><OMS cd="weylalgebra1" name="diffop"/>
<OMA><OMS cd="arith1" name="times"/>
<OMA><OMS cd="arith1" name="times"/>
<OMA><OMS cd="arith1" name="power"/>
<OMV name="x"/>
<OMV name="m"/>
</OMA>
<OMA><OMS cd="arith1" name="power"/>
<OMV name="dx"/>
<OMV name="n"/>
</OMA>
</OMA>
<OMA><OMS cd="arith1" name="power"/>
<OMV name="dy"/>
<OMV name="r"/>
</OMA>
</OMA>
<OMA><OMS cd="list1" name="list"/>
<OMA><OMS cd="list1" name="list"/>
<OMV name="x"/>
<OMV name="y"/>
</OMA>
<OMA><OMS cd="list1" name="list"/>
<OMV name="dx"/>
<OMV name="dy"/>
</OMA>
</OMA>
</OMA>
<OMV name="f"/>
</OMA>
<OMA><OMS cd="arith1" name="times"/>
<OMA><OMS cd="arith1" name="power"/>
<OMV name="x"/>
<OMV name="m"/>
</OMA>
<OMA><OMS cd="weylalgebra1" name="partialdiff"/>
<OMV name="f"/>
<OMA><OMS cd="list1" name="list"/>
<OMA><OMS cd="list1" name="list"/>
<OMV name="x"/>
<OMV name="n"/>
</OMA>
<OMA><OMS cd="list1" name="list"/>
<OMV name="y"/>
<OMV name="r"/>
</OMA>
</OMA>
</OMA>
</OMA>
</OMA>
</OMOBJ>
<math xmlns="http://www.w3.org/1998/Math/MathML">
<apply><csymbol cd="relation1">eq</csymbol>
<apply><csymbol cd="weylalgebra1">act</csymbol>
<apply><csymbol cd="weylalgebra1">diffop</csymbol>
<apply><csymbol cd="arith1">times</csymbol>
<apply><csymbol cd="arith1">times</csymbol>
<apply><csymbol cd="arith1">power</csymbol><ci>x</ci><ci>m</ci></apply>
<apply><csymbol cd="arith1">power</csymbol><ci>dx</ci><ci>n</ci></apply>
</apply>
<apply><csymbol cd="arith1">power</csymbol><ci>dy</ci><ci>r</ci></apply>
</apply>
<apply><csymbol cd="list1">list</csymbol>
<apply><csymbol cd="list1">list</csymbol><ci>x</ci><ci>y</ci></apply>
<apply><csymbol cd="list1">list</csymbol><ci>dx</ci><ci>dy</ci></apply>
</apply>
</apply>
<ci>f</ci>
</apply>
<apply><csymbol cd="arith1">times</csymbol>
<apply><csymbol cd="arith1">power</csymbol><ci>x</ci><ci>m</ci></apply>
<apply><csymbol cd="weylalgebra1">partialdiff</csymbol>
<ci>f</ci>
<apply><csymbol cd="list1">list</csymbol>
<apply><csymbol cd="list1">list</csymbol><ci>x</ci><ci>n</ci></apply>
<apply><csymbol cd="list1">list</csymbol><ci>y</ci><ci>r</ci></apply>
</apply>
</apply>
</apply>
</apply>
</math>
weylalgebra1.act(weylalgebra1.diffop($x ^ $m * $dx ^ $n * $dy ^ $r, [[$x , $y] , [$dx , $dy]]), $f) = $x ^ $m * weylalgebra1.partialdiff($f, [[$x , $n] , [$y , $r]])