<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow> <mml:mi mathvariant="bold">N</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
<mml:mi mathvariant="bold">g</mml:mi>
<mml:mi mathvariant="bold">a</mml:mi>
<mml:mi mathvariant="bold">t</mml:mi>
<mml:mi mathvariant="bold">i</mml:mi>
<mml:mi mathvariant="bold">v</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
<mml:mspace width="0.25em"/>
<mml:mi mathvariant="bold">p</mml:mi>
<mml:mi mathvariant="bold">r</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
<mml:mi mathvariant="bold">d</mml:mi>
<mml:mi mathvariant="bold">i</mml:mi>
<mml:mi mathvariant="bold">c</mml:mi>
<mml:mi mathvariant="bold">t</mml:mi>
<mml:mi mathvariant="bold">i</mml:mi>
<mml:mi mathvariant="bold">v</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
<mml:mspace width="0.25em"/>
<mml:mi mathvariant="bold">v</mml:mi>
<mml:mi mathvariant="bold">a</mml:mi>
<mml:mi mathvariant="bold">l</mml:mi>
<mml:mi mathvariant="bold">u</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
<mml:mo>=</mml:mo>
<mml:mi mathvariant="bold">s</mml:mi>
<mml:mi mathvariant="bold">p</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
<mml:mi mathvariant="bold">c</mml:mi>
<mml:mi mathvariant="bold">i</mml:mi>
<mml:mi mathvariant="bold">f</mml:mi>
<mml:mi mathvariant="bold">i</mml:mi>
<mml:mi mathvariant="bold">c</mml:mi>
<mml:mi mathvariant="bold">i</mml:mi>
<mml:mi mathvariant="bold">t</mml:mi>
<mml:mi mathvariant="bold">y</mml:mi>
<mml:mo>*</mml:mo>
<mml:mfenced close=")" open="("> <mml:mrow> <mml:mn mathvariant="bold">1</mml:mn>
<mml:mo>&#8722;</mml:mo>
<mml:mi mathvariant="bold">p</mml:mi>
<mml:mi mathvariant="bold">r</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
<mml:mi mathvariant="bold">v</mml:mi>
<mml:mi mathvariant="bold">a</mml:mi>
<mml:mi mathvariant="bold">l</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
<mml:mi mathvariant="bold">n</mml:mi>
<mml:mi mathvariant="bold">c</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
</mml:mrow>
</mml:mfenced>
<mml:mo>/</mml:mo>
<mml:mo stretchy="true">[</mml:mo>
<mml:mi mathvariant="bold">s</mml:mi>
<mml:mi mathvariant="bold">p</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
<mml:mi mathvariant="bold">c</mml:mi>
<mml:mi mathvariant="bold">i</mml:mi>
<mml:mi mathvariant="bold">f</mml:mi>
<mml:mi mathvariant="bold">i</mml:mi>
<mml:mi mathvariant="bold">c</mml:mi>
<mml:mi mathvariant="bold">i</mml:mi>
<mml:mi mathvariant="bold">t</mml:mi>
<mml:mi mathvariant="bold">y</mml:mi>
<mml:mo>*</mml:mo>
<mml:mfenced close="]" open="("> <mml:mrow> <mml:mn mathvariant="bold">1</mml:mn>
<mml:mo>&#8722;</mml:mo>
<mml:mi mathvariant="bold">p</mml:mi>
<mml:mi mathvariant="bold">r</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
<mml:mi mathvariant="bold">v</mml:mi>
<mml:mi mathvariant="bold">a</mml:mi>
<mml:mi mathvariant="bold">l</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
<mml:mi mathvariant="bold">n</mml:mi>
<mml:mi mathvariant="bold">c</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
<mml:mo>+</mml:mo>
<mml:mfenced close=")" open="("> <mml:mrow> <mml:mn mathvariant="bold">1</mml:mn>
<mml:mo>&#8722;</mml:mo>
<mml:mi mathvariant="bold">s</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
<mml:mi mathvariant="bold">n</mml:mi>
<mml:mi mathvariant="bold">s</mml:mi>
<mml:mi mathvariant="bold">i</mml:mi>
<mml:mi mathvariant="bold">t</mml:mi>
<mml:mi mathvariant="bold">i</mml:mi>
<mml:mi mathvariant="bold">v</mml:mi>
<mml:mi mathvariant="bold">i</mml:mi>
<mml:mi mathvariant="bold">t</mml:mi>
<mml:mi mathvariant="bold">y</mml:mi>
</mml:mrow>
</mml:mfenced>
<mml:mo>*</mml:mo>
<mml:mi mathvariant="bold">p</mml:mi>
<mml:mi mathvariant="bold">r</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
<mml:mi mathvariant="bold">v</mml:mi>
<mml:mi mathvariant="bold">a</mml:mi>
<mml:mi mathvariant="bold">l</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
<mml:mi mathvariant="bold">n</mml:mi>
<mml:mi mathvariant="bold">c</mml:mi>
<mml:mi mathvariant="bold">e</mml:mi>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:math>