hasTopic: RDF schema and usage

<rdf:Property rdf:about="http://www.w3.org/2002/01/bookmark#hasTopic">
    <rdfs:label xml:lang="en">has topic</rdfs:label>
    <rdfs:comment>relates a resource to a topic.
        A resource can have zero or more hasTopic properties.</rdfs:comment>
    <rdfs:isDefinedBy rdf:resource="http://www.w3.org/2002/01/bookmark#"/>
</rdf:Property>

<rdf:Description rdf:about="http://annotest.w3.org/…/3ACF6D75">
     <bm:hasTopic> http://www.w3.org/2002/04/26-face#pupil </bm:hasTopic>   
</rdf:Description>