<rdf:Property rdf:ID="IsAnchor">
<rdfs:domain rdf:resource="#SvgEntity"/>
<rdfs:range rdf:resource="#boolean"/>
</rdf:Property>
<rdf:Property rdf:ID="Labelled">
<rdfs:domain rdf:resource="#SvgEntity"/>
<rdfs:range rdf:resource="#boolean"/>
</rdf:Property>
<rdf:Property rdf:ID="LabelledBy">
<rdfs:subPropertyOf rdf:resource="#Labelled"/>
<rdfs:range rdf:resource="#SvgEntity"/>
</rdf:Property>
And here is the full (RDF) schema...