data/mathtoweb/271.mml
<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mstyle displaystyle="true"><mn>1</mn><mo>-</mo><mi>a</mi><mspace width="0.167em" /><msub><mrow><mover accent="true"><mo>∂</mo><mo>¯</mo></mover></mrow><mi>p</mi></msub></mstyle></mrow></math>