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    <title>fractions linethickness</title>
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    <!-- From the MathML spec:
         'The default value is "medium", "thin" is thinner, but visible,
         "thick" is thicker; the exact thickness of these is left up to the
         rendering agent.'
         'A number without a unit is intepreted as a multiple of the default
         value.'
         
         Here are the linethickness values used by WebKit:
         
         gLineThin = 0.33f;
         gLineMedium = 1.f;
         gLineThick = 3.f;
      -->

    <math mathsize="32px">
      <mfrac linethickness="0.33px"><mn>1</mn><mn>2</mn></mfrac>
      <mfrac linethickness="1px"><mn>1</mn><mn>2</mn></mfrac>
      <mfrac linethickness="3px"><mn>1</mn><mn>2</mn></mfrac>
      <mfrac linethickness="5px"><mn>1</mn><mn>2</mn></mfrac>
    </math>

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