DAML+OIL for Application Developers - slide "RDF Abbreviated Syntax"

to avoid exposing content, RDF defines an abbreviated syntax that encodes everything as attribute values, e.g. <rdf:Description ... predicate="literal" .../> is equivalent to <rdf:Description ...> <predicate>literal</predicate> ... </rdf:Description>

XML prohibits using the same attribute more than once in an element, so we can't say


<!-- BAD: -->
<rdf:Description ... predicate="literal1" predicate="literal2"/>

but we can say


<!-- GOOD: -->
<rdf:Description ... predicate="literal1"/>
<rdf:Description rdf:about="sameURI" predicate="literal2"/>