- From: Smith, Michael K <michael.smith@eds.com>
- Date: Thu, 19 Jun 2003 11:00:19 -0500
- To: Sean Bechhofer <seanb@cs.man.ac.uk>, www-webont-wg@w3.org
Wine.owl has an xml:base declaration. My local copy of food.owl does also. For some reason, the copy if food.owl out on the web site does not. I must have slipped up somewhere. It will. - Mike -----Original Message----- From: Sean Bechhofer [mailto:seanb@cs.man.ac.uk] Sent: Thursday, June 19, 2003 8:27 AM To: www-webont-wg@w3.org Subject: Namespaces in guide ontologies I believe there are still some anomolies in the guide ontologies at: http://www.w3.org/2001/sw/WebOnt/guide-src/food.owl http://www.w3.org/2001/sw/WebOnt/guide-src/wine.owl In, for example, food.owl, there is an xml namespace declaration in the RDF header: xmlns="http://www.w3.org/2001/sw/WebOnt/guide-src/food#" 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: http://www.w3.org/2001/sw/WebOnt/guide-src/food.owl#Duck rdf:type http://www.w3.org/2001/sw/WebOnt/guide-src/food#DarkMeatFowl 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: xml:base="http://www.w3.org/2001/sw/WebOnt/guide-src/food" 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 http://www.w3.org/2001/sw/WebOnt/guide-src/food.owl#DarkMeatFowl 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 one..... Cheers, Sean -- Sean Bechhofer seanb@cs.man.ac.uk http://www.cs.man.ac.uk/~seanb
Received on Thursday, 19 June 2003 12:01:10 UTC