Xslt variable(node set)

        <span xmlns=''><p>
         </p><p><span style='font-family:Consolas'><span style='color:blue'><</span><span style='color:#2b91af'>xsl:variable</span><span style='color:blue'>
        </span><span style='color:red'>name</span><span style='color:blue'> =</span>"<span style='color:blue'>persons</span>"<span style='color:blue'>
        </span><span style='color:red'>select</span><span style='color:blue'>=</span>"<span style='color:blue'>/all/persons/p</span>"<span style='color:blue'> />
        </span></span></p><p><span style='font-family:Consolas'><span style='color:blue'><</span><span style='color:#2b91af'>xsl:variable</span><span style='color:blue'>
        </span><span style='color:red'>name</span><span style='color:blue'> =</span>"<span style='color:blue'>persons1</span>"<span style='color:blue'>>
        </span></span></p><p><span style='font-family:Consolas'><span style='color:blue'>    <</span><span style='color:#2b91af'>xsl:copy-of</span><span style='color:blue'>
        </span><span style='color:red'>select</span><span style='color:blue'>=</span>"<span style='color:blue'>/all/persons/p</span>"<span style='color:blue'>/>
        </span></span></p><p><span style='font-family:Consolas'><span style='color:blue'></</span><span style='color:#2b91af'>xsl:variable</span><span style='color:blue'>>
        </span></span></p><p>
         </p><p>The difference between them is that persons has parent, but persons1 has not parent because it is a deep copy.</p></span>