data/mathtoweb/212.mml
<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>ψ</mi><mrow><mo form="prefix">(</mo><mi>a</mi><mo>+</mo><mi>b</mi><mo form="postfix">)</mo></mrow><mo>=</mo><mi>ψ</mi><mrow><mo form="prefix">(</mo><mi>a</mi><mo form="postfix">)</mo></mrow><mover accent="true"><mo>+</mo><mo stretchy="true">˜</mo></mover><mi>ψ</mi><mrow><mo form="prefix">(</mo><mi>b</mi><mo form="postfix">)</mo></mrow></mrow></math>