Informative Image Example

Example 5: Mathematical Expressions

Overview

To ensure accessibility, mathematical expressions should be incorporated into a web resource using MathML, a W3C approved mark-up language for mathematical expressions based on XML. MathML provides two sets of tags: Presentation MathML and Content MathML. Presentation MathML visually presents the mathematical notation as part of normal web resources. Content MathML conveys the mathematical meaning of the expression for applications where the semantics plays a larger role, such as scientific software or voice synthesis.

Use of MathML benefits not only people with disability by providing access to mathematical expressions through means other than visual, but also the general user as it facilitates import and export of mathematical expressions on the web and provides high-quality presentation that is not achieved by conventional word-processing.

Editing

Editing MathML is not intuitive or compact, and is not intended to be done by hand. Utilities are available on the web for converting mathematical expressions into MathML from conventional methods (e.g., from TeX notation to MathML).

Browser Support

Major graphical browsers support MathML in one way or the other. Recent versions of Firefox directly support MathML; Internet Explorer and Opera support MathML through plug-ins such as MathPlayer for Internet Explorer.

Visit MathML section of W3C website for more information.

Example

image of mathematical expression rendered by MathML

XML Source: Presentation XML

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <mrow>
    <msup>
      <mi>&#945;</mi>
      <mn>2</mn>
    </msup>
    <mo>+</mo>
    <msup>
      <mi>&#946;</mi>
      <mn>2</mn>
    </msup>
    <mo>&#8804;</mo>
    <mn>1</mn>
  </mrow>
</math>