A Simple RDF Graph with namespaces on predicates 
       <rdf:Description rdf:about="#FullSlide">
          <axsvg:LabelledBy>
              <rdf:Description rdf:about="#BottomLegend"/>
          </axsvg:LabelledBy>
       </rdf:Description>
       <rdf:Description rdf:about="#FullSlide">
          <axsvg:GraphicsType>
              Chart
          </axsvg:GraphicsType>
       </rdf:Description>