\hypertarget{identity}{}\subsection{Identity}\label{identity}
XML is not just a tree, but a tree with pointers. An xs:IDREF points to an element with an xs:ID within the same document. An xs:ID identifies the immediately containing element. Typically this is an xs:ID attribute on the element, though it may also be xs:ID simple content.

In RDF we identify the element {\em content\/}, by assigning it a URI. This URI is the object of the statement representing the element occurrence.

\begin{itemize}
\item \hyperlink{attributeid}{attribute identity}\item \hyperlink{elementid}{element identity} \end{itemize}
