<!DOCTYPE html>
<html>
<head>
  <title>op-dict largeop</title>
  <link rel="match" href="op-dict-6-ref.html">
</head>
<body>
  <math displaystyle="true">
    <mrow>
      <mo>&#x2211;</mo>
    </mrow>
  </math>
</body>
</html>
