<p>Is this right for When 4 &lt; 5 and 1 &lt; 2 ?</p>

<pre><code>&lt;xsl:when test="4 &amp;lt; 5 AND 1 &amp;lt; 2" &gt;
&lt;!-- do something --&gt;
&lt;/xsl:when&gt;
</code></pre>

From
XML.com
:
Like xsl:if instructions, xsl:when
  elements can have more elaborate
  contents between their start- and
  end-tags—for example, literal result
  elements, xsl:element elements, or
  even xsl:if and xsl:choose elements—to
  add to the result tree. Their test
  expressions can also use all the
  tricks and operators that the xsl:if
  element's test attribute can use, such
  as and, or, and function calls, to
  build more complex boolean
  expressions.