rec-power4

W3C sample	WIRIS
[N/A]	$power x 3$

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <apply>
    <csymbol cd="arith1">power</csymbol>
    <ci>x</ci>
    <cn>3</cn>
  </apply>
</math>

Author: MathML 2 Recommendation