min1

min(x, x not in B, x^2) using <reln>

W3C sample WIRIS
x x B x 2
<math xmlns="http://www.w3.org/1998/Math/MathML">
  <apply>
    <min/>
    <bvar>
      <ci>x</ci>
    </bvar>
    <condition>
      <reln>
        <notin/>
        <ci>x</ci>
        <ci type="set">B</ci>
      </reln>
    </condition>
    <apply>
      <power/>
      <ci>x</ci>
      <cn>2</cn>
    </apply>
  </apply>
</math>

Author: Design Science, Inc. (E. Cannon, E. Tabacman, R.Miner)