[xsl] Got an XSLT function that does value intersection (not identity intersection)?

["Roger L Costello costello@xxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Hi Folks,

I have an XML document that consists of <row> elements:

<Document>
    <row>
        <x>1</x>
       <y>2</y>
    </row>
    <row>
        <x>3</x>
       <y>4</y>
    </row>
    <row>
        <x>1</x>
       <y>2</y>
    </row>
</Document>

I want to eliminate duplicate rows.

The XPath intersect operator is appealing:

$document intersect $document

because intersect eliminates duplicates. Unfortunately, that doesn't work
because row1 and row2 are "duplicates" only if they are the exact same <row>
element, i.e., same identity.

I need an intersection operator that eliminates duplicates based on value.
Since row[1] and row[3] above have the same elements with the same values,
they are duplicates.

Do you have a function that does intersection based on value, not identity?
Or, perhaps you recommend another way to eliminate duplicates?

/Roger