Considering the sample xml below, I want to initialise an xsl:variable with the maximum number of c-child nodes any of the b-nodes have (i.e. in the sample below, I would like the variable to be set to 3):

<a>
  <b>
    <c>1</c>
    <c>2</c>
  </b>
  <b>
    <c>7785</c>
  </b>
  <b>
    <c>100</c>
    <c>101</c>
    <c>102</c>
  </b>
</a>

Any help is greatly appreciated.

With XPath 2.0, it's easy:

(with <a> as the context node)

max(b/count(c))

With 1.0 as always it's more tortuous. The usual way to do max/min in 1.0 is to sort and take the first/last:

<xsl:variable name="max">
  <xsl:for-each select="b"/>
    <xsl:sort select="count(c)" data-type="number"/>
    <xsl:if test="position()=last()">
      <xsl:value-of select="count(c)"/>
    </xsl:if>
  </xsl:for-each>
</xsl:variable>

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

Thanks Michael, now I'm really eager to go to XPath 2.0!