<owl:Class rdf:ID="SVGFigure_Chart">
      <owl:equivalentClass>
          <owl:Restriction>
              <owl:onProperty rdf:about="#ChartType"/>
              <owl:cardinality
                  rdf:dataype="...#nonNegativeInteger">
                  1
              </owl:cardinality>
          </owl:Restriction>
      </owl:equivalentClass>
  </owl:Class>