<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <semantics>
    <mi>&eta;</mi>
    <annotation-xml encoding="MathML-Content">
      <ci>&eta;</ci>
    </annotation-xml>
    <annotation encoding="SnuggleTeX">\[ \eta \]</annotation>
    <annotation encoding="LaTeX">\[ \eta \]</annotation>
    <annotation encoding="Maxima">%eta</annotation>
  </semantics>
</math>
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <semantics>
    <mi>&eta;</mi>
    <annotation encoding="SnuggleTeX">\[ \eta \]</annotation>
  </semantics>
</math>
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mi>&eta;</mi>
</math>
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <ci>&eta;</ci>
</math>
%eta