
<!DOCTYPE math
  PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<math xmlns="http://www.w3.org/1998/Math/MathML">
<apply>
  <exists/>
  <bvar><ci> x </ci></bvar>
  <apply><eq/>
    <apply>
      <fn><ci> f </ci></fn>
      <ci> x </ci>
    </apply>
    <cn>0</cn>
  </apply>
</apply>
</math>