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Namespaces in guide ontologies

From: Sean Bechhofer <seanb@cs.man.ac.uk>
Date: Thu, 19 Jun 2003 14:27:08 +0100 (GMT Daylight Time)
To: www-webont-wg@w3.org
Message-ID: <Pine.WNT.4.44.0306191405160.1780-100000@potato>

I believe there are still some anomolies in the guide ontologies at:


In, for example, food.owl, there is an xml namespace declaration in the
RDF header:


This means that any "vanilla" elements used in this scope will be in this
namespace, e.g.

<DarkMeatFowl rdf:ID="Duck"/>             [1]

However according to my understanding of the rules for resolving names,
which seems to be borne out with experimental evidence from examining the
result of parsers, the xmlns declaration does *not* apply to attributes --
by default they get resolved to the base URI of the document. Somebody
*please* shout if I'm wrong here because to be honest I find this
namespace resolution highly confusing.... Assuming that I'm right though,
this means that the statement above is actually saying:




which is not, I think, what is intended. In order to make sure that the
attributes end up in the same namespace, you need (I think) an xml:base
attribute, e.g:


As they currently stand, I believe the example ontologies are *not* DL due
to this mismatch, as a number of things are not explicity typed. For
example, there is a statement:

<owl:Class rdf:ID="DarkMeatFowl"/>

This then refers to a uri


which is not the same "DarkMeatFowl" used in the earlier rdf:type
assertion, and this means that [1] is using an "untyped" class.

I think the /TR/owl-guide ontologies have the same problem.

It might be worth a note in one of the documents about this kind of thing
-- as I said above, it gives me a headache and I'm sure I'm not the only



Sean Bechhofer
Received on Thursday, 19 June 2003 09:28:18 UTC

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