From: pat hayes (phayes@ai.uwf.edu)
Date: 06/07/01
> > What I want is that the value of myProperty can be > > *any* class. > >Then the range of it is rdfs:Class. > > :myProperty rdfs:range rdfs:Class . > > > > :x rdfs:range > > > [ daml:intersectionOf > > > (:Class [ rdfs:subClassOf :Animal ]) ] . > > > XML RDF of these things available upon request... > > > > I would very much appreciate seeing the last sample above > > in DAML+OIL. > ><daml:Class rdf:ID="x"> > <rdfs:range> > <rdf:Description> > <daml:intersectionOf parseType="daml:collection"> > <daml:Class rdf:ID="Class"/> > <rdf:Description> > <rdfs:subClassOf rdf:resource="#Animal"/> > </rdf:Description> > </daml:intersectionOf> > </rdf:Description> > </rdfs:range> ></daml:Class> > >In prose: the range of class "x" is an intersectionOf "#Class" and >something which is the subClassOf "#Animal"; which most likely isn't >what you really want to say. > > > (a) assert that something is a subclass of Animal > > (b) denote the set of all subclasses of Animal? > >[ rdfs:subClassOf :Animal ] should be read as "something which is a >subClassOf Animal". Not all of the subClasses, one specific sub class. >So, (a). > > > Your example seems to rely on (b). > >Nope. There is a way that one might be led to think of (b), however. In general, an expression denoting an 'anonymous' entity can be understood as denoting a property (the one shared by all the possible entities that could be the anonymous entity), so that with this understanding, [rdfs:subClassOf :Animal] would refer to the property of being a subclass of Animal. And then, given that this is a class-based language where a property is understood to be a class, this might easily be taken to refer to the class of all subclasses of Animals. In sum, there is a natural conceptual path from 'anonymous thingie' to 'class of thingies'. So the upshot is, that we probably need to be extra-sensitive to this natural slope and put up guard rails in the DAML documentation. Thanks for bringing this up, guys. Pat Hayes --------------------------------------------------------------------- IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola, FL 32501 (850)202 4440 fax phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes
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