W3C home > Mailing lists > Public > public-webont-comments@w3.org > December 2003

RE: Annotation properties with range and other rdf:types

From: Holger Knublauch <holger@SMI.Stanford.EDU>
Date: Wed, 3 Dec 2003 13:32:07 -0800
To: "'Jim Hendler'" <hendler@cs.umd.edu>, <public-webont-comments@w3.org>
Message-ID: <006601c3b9e4$e7817950$2c2141ab@holgersmi>

> Holger, I must admit some confusion - if you know the types and 
> properties of these things, why do you want to make them annotations? 
> If you goal is to have metaclasses (I.e. classes with properties) you 
> can certainly use OWL Full, it was designed to allow that.

Yes, I could use OWL Full, but I think the feature of (typed)
annotation properties is of such a great importance to ontology
designers that it should also work for OWL DL.  While I could
delete all annotations temporarily before I send the ontology to the
classifier, the information will still be stored in the ontology,
making the file difficult to share on the Web.  My apologies if
I lack the technical background of the OWL language theory that
the WebOnt group has, but what is the problem with allowing it
in OWL DL?

Our typical use case is to allow the definition of metaclasses and
property metaclasses which hold extra information.  For example,
a property metaclass could introduce an extra property "unit"
or a class could be annotated with an "author" and "change date".
This information is completely irrelevant to the classifier,
and could be easily ignored if the property is flagged as an
annotation property.  I don't see however, why this excludes the
use of range information on the annotation property.

>   So, in essence, you cannot have it both ways -- if you want to live 
> in DL, you need to accept its restrictions.  If you don't want these 
> restrictions, you should use OWL Full -- afraid that logic will not 
> let us have our cake and eat it too (believe me, the WG tried hard to 
> find a way to do that :->)

My impression is that, in this aspect, OWL has been designed
to fit the needs of a classifier, and not from a user's or tool
perspective, but you know more than I do.

>   For what you are suggesting doing, why can you not just use RDF 
> comments, etc. or to define things directly in OWL?

Because from a user's perspective annotation p's should appear
just like other properties - he or she should be able to specify
extra information (e.g. range) on the property so that it is
later easier to enter values for the property.

Received on Wednesday, 3 December 2003 16:27:49 UTC

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