<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:msup>
<mml:mi mathvariant="bold-italic">g</mml:mi>
<mml:mo mathvariant="bold">′</mml:mo>
</mml:msup>
<mml:mo mathvariant="bold" stretchy="false">(</mml:mo>
<mml:mi mathvariant="bold-italic">η</mml:mi>
<mml:mo mathvariant="bold" stretchy="false">)</mml:mo>
</mml:math>