rec-root1

a to the nth power

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <apply>
    <csymbol cd="arith1">root</csymbol>
    <ci>a</ci>
    <semantics>
      <ci>n</ci>
      <annotation-xml cd="mathmltypes" name="type" encoding="MathML-Content">
        <ci>integer</ci>
      </annotation-xml>
    </semantics>
  </apply>
</math>

Author: MathML 2 Recommendation