Example
In the following example, the <alternatives> element is used to wrap a mathematical expression encoded in MathML with a graphic image of the same expression for use in environments where MathML is not supported.
...
<p>The following discussion makes use of
some properties of the three-by-three identity matrix:</p>
<disp-formula>
<alternatives>
<mml:math>
<mml:mrow>
<mml:mo> ( </mml:mo>
<mml:mtable>
<mml:mtr>
<mml:mtd> <mml:mn>1</mml:mn> </mml:mtd>
<mml:mtd> <mml:mn>0</mml:mn> </mml:mtd>
<mml:mtd> <mml:mn>0</mml:mn> </mml:mtd>
</mml:mtr>
<mml:mtr>
<mml:mtd> <mml:mn>0</mml:mn> </mml:mtd>
<mml:mtd> <mml:mn>1</mml:mn> </mml:mtd>
<mml:mtd> <mml:mn>0</mml:mn> </mml:mtd>
</mml:mtr>
<mml:mtr>
<mml:mtd> <mml:mn>0</mml:mn> </mml:mtd>
<mml:mtd> <mml:mn>0</mml:mn> </mml:mtd>
<mml:mtd> <mml:mn>1</mml:mn> </mml:mtd>
</mml:mtr>
</mml:mtable>
<mml:mo> ) </mml:mo>
</mml:mrow>
</mml:math>
<graphic xlink:href="images/identity-matrix">
<alt-text>A three-by-three identity matrix.</alt-text>
<permissions>
<copyright-statement>© 1998-2003 W3C ® (MIT, ERCIM,
Keio); used by permission</copyright-statement>
<copyright-year>1998-2003</copyright-year>
<copyright-holder>W3C ® (MIT, ERCIM,
Keio)</copyright-holder>
</permissions>
</graphic>
</alternatives>
</disp-formula>
<p>
Analogous observations hold for identity matrices of different sizes.
</p>
...
The graphic rendering of the mathematical expression is:
(MathML example and graphic from Mathematical Markup Language (MathML) Version 2.0 (Second Edition), W3C Recommendation 21 October 2003, ed. David Carlisle et al., © 1998-2003 W3C® (MIT, ERCIM, Keio), all rights reserved. Used by permission.)