rec-set1

set: {b, a, c}

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <apply>
    <csymbol cd="set1">set</csymbol>
    <ci>b</ci>
    <ci>a</ci>
    <ci>c</ci>
  </apply>
</math>

Author: MathML 2 Recommendation