Hi,
I do not really understand the need for rdfs:Class:
owl:Class is already defined with rdfs:subClassOf rdfs:Class (same thing
for the properties). So its is a transitivity issue and it depends on
the used reasoner to resolve that issue.
owl:Class is defined as a subclass of rdfs:Class *in the OWL
specifications*. The RDF/RDFS specification does not say anything about
owl:Class. So, from a pure RDFS perspective, owl:Class has as much
meaning as, e.g., xyz:abc. The fact that someone defines *somewhere*
that xyz:abc is a subclass of rdfs:Class is irrelevant from a pure RDFS
system point of view. As I said in my example, a SPARQL query would not
be able to retrieve the OWL classes or properties that are not directly
asserted as RDFS classes or properties (unless the SPARQL engine
implements part of the OWL spec, which is rarely the case).
Now, that's a small issue but there is no disadvantage of putting the
additional types, as far as I know.
This implies for me that I have to add rdfs:class to every owl:class
based definition of every ontology. That's makes no real sense for me,
sorry. It's somehow a step backward.
Yet, it's easy to make a programme that deals equally well with all
these values, whereas it is difficult to ensure that everybody will use
the three datatypes mentioned in the range assertion.
That's why we've defined that restriction, because the use of these
datatypes is well defined in XSD and they are support from the standard
programming languages, which might process it as this kind of datatype.
In the absence of range assertion, such values as:
ex:sim :distance "very similar" .
ex:sim :distance "+++"^^xsd:string .
This definition is somehow unspecific, because this could only exists
with a specific definition of these values, which I could at least map
to a numeric value, e.g. scale 1-5. I think the numeric value is all I
need, because values of sim:distance and sim:weight are somehow
technical and need an extra translation step for human reading. So I
could define the specific human readable term in different languages
(English, Spain, French, ...).
Cheers,
Bob
