RE: Intersection of properties?

Not really relevant for the core discussion of this thread, but...

A.P. Gibson wrote:

>Going out on a limb here - and I dont expect this will happen - but I
>dont see why OWL-Full can't be furnished with the appropriate syntax for
>*potential* expressivity like role conjunction so that people will a)
>know what extentions are theoretically possible and therefore be able to
>ask for them and b) be able to play around with them (albeit only
>syntactiacally) and generate the kinds of use cases that you and the
>working group are looking for, possibly even with tool support for the
>process.

OWL Full isn't intended to be a kind of "first look" language for
experimenting with features which may or may not become OWL DL features in
the future. 

In OWL 1, OWL Full shared with OWL DL the same principle language features,
such as restrictions, boolean class expressions, property characteristics,
nominals, etc. So the main difference between these two languages was not on
the set of supported language features, but on the different kinds of
semantics they provide. OWL DL is based on a description logic (SHOIN),
while OWL Full is an extension of the RDF(S) semantics. 

For example, RDFS allows you to conclude that every class of individuals is
itself an individual within the universe, while this is not a conclusion
which you would expect from a description logic. Another difference is that
OWL Full gives semantic meaning to every RDF graph, while OWL DL's semantic
interpretations are restricted to only a certain subset of RDF graphs
(actually, OWL DL's syntax is an "abstract syntax", and not every RDF graph
can be mapped to a well-formed expression of this abstract syntax). 

In OWL 1, a lot of effort was spent in having the semantics of OWL DL and
OWL Full reasonably close to each other. While perfect alignment is not
possible, as one can see from the differences mentioned above, one should at
least try to avoid that the semantics of these two languages deviate too
extremely. Having additional "experimental" features for OWL 2 Full would
rather be against this idea, IMO.

Cheers,
Michael

--
Dipl.-Inform. Michael Schneider
FZI Forschungszentrum Informatik Karlsruhe
Abtl. Information Process Engineering (IPE)
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Email: Michael.Schneider@fzi.de
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