The example on intersection using xsl:merge in Section 15.8 is missing an '>' at the end of the <xsl:if ...> instruction (5th line from bottom in the example):

<xsl:merge>
  <xsl:merge-source>                  
    <xsl:merge-input select="1 to 30">
      <xsl:merge-key select="."/>
    </xsl:merge-input>
  </xsl:merge-source>
  <xsl:merge-source>                  
    <xsl:merge-input select="20 to 40">
      <xsl:merge-key select="."/>
    </xsl:merge-input>
  </xsl:merge-source>
  <xsl:merge-action>
    <xsl:if test="count(current-group()) eq 2"
      <xsl:value-of select="current-grouping-key()"/>
    </xsl:if>
  </xsl:merge-action>
</xsl:merge>