rec-interval1

W3C sample	WIRIS
[N/A]	$interval_cc a b$

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <apply>
    <csymbol cd="interval1">interval_cc</csymbol>
    <ci>a</ci>
    <ci>b</ci>
  </apply>
</math>

Author: MathML 2 Recommendation