W3C home > Mailing lists > Public > public-owl-dev@w3.org > January to March 2007

RE: declaredAs

From: Boris Motik <bmotik@cs.man.ac.uk>
Date: Fri, 26 Jan 2007 11:27:13 -0000
To: "'Matthew Horridge'" <matthew.horridge@cs.man.ac.uk>, <public-owl-dev@w3.org>
Message-ID: <000301c7413c$ecf71f10$27c35882@wolf>


Well, we've been thinking about this, but decided not to do so for an
important reason. Consider an ontology O containing an object property P for
which there is no declaration. A serialization of O into an RDF graph must
ensure the following two things:

(1) When you parse the graph, you must be able to decode the type of P.
(2) The parsing should correctly restore the "declaredness" status of P --
that is, after parsing, the ontology should not contain a declaration for P.

Now the problem is that, to ensure compatibility with OWL DL, we use
rdf:type to ensure (1). In the worst case, you really need to include a

(3) <P, rdf:type, owl:ObjectProperty>

so that, when you parse the graph, you know what the type of P is. But then,
you should not use rdf:type to reflect the "declaredness" status of P in an
ontology; otherwise, any ontology that contains the triple (3) will also
contain a declaration for P.

We weren't able to find a way out of this problem and have, consequently,
introduced the owl:declaredAs property.

Thanks anyway for this suggestion!

Sincerely yours,


> -----Original Message-----
> From: public-owl-dev-request@w3.org [mailto:public-owl-dev-request@w3.org]
> On Behalf Of Matthew Horridge
> Sent: 26 January 2007 10:06
> To: public-owl-dev@w3.org
> Subject: declaredAs
> All,
> I've been working on an OWL 1.1 parser/renderer recently, and I
> wondered if we could just use rdf:type instead of owl:declaredAs for
> entity declarations in the RDF mapping.  I can't immediately see a
> problem with doing this, and I believe it would improve backwards
> compatibility with the existing "OWL 1.0" RDF/XML mapping.  Any
> thoughts?
> Cheers,
> Matthew
Received on Friday, 26 January 2007 14:18:33 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 20:58:14 UTC