rec-subset1

A is subset of B as <apply>

W3C sample	WIRIS
[N/A]	$subset A B$

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <apply>
    <csymbol cd="set1">subset</csymbol>
    <ci>A</ci>
    <ci>B</ci>
  </apply>
</math>

Author: MathML 2 Recommendation