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RE: base in OWL-S files

From: Collin Hsu <collin@seu.edu.cn>
Date: Sun, 17 Oct 2004 16:00:20 +0800
To: <public-sws-ig@w3.org>
Cc: "'Daniel Elenius'" <daele@ida.liu.se>
Message-ID: <E1CJ5yg-0005NL-Qu@frink.w3.org>

http://www.w3.org/DesignIssues/Fragment.html may be helpful in understanding
the optional "#" at the end of URIs for Web resources. 

Regards,
Collin 

> -----Original Message-----
> From: public-sws-ig-request@w3.org 
> [mailto:public-sws-ig-request@w3.org] On Behalf Of Daniel Elenius
> Sent: Friday, October 15, 2004 5:51 AM
> To: public-sws-ig@w3.org
> Subject: xml:base in OWL-S files
> 
> 
> Working with the OWL-S files, and struggling with imports in 
> protege, I have looked at some details of the OWL-S files, 
> in, well some detail :) And I want to discuss the following issue.
> 
> All the OWL-S files now have an xml:base defined, such as
> 
> xml:base="&process;"
> 
> in Process.owl, where &process; is defined by <!ENTITY 
> process "http://www.daml.org/services/owl-s/1.1/Process.owl">
> 
> But ordinary namespace prefixes have a hash (#) in the end, such as:
> 
> xmlns:grounding= "&grounding;#"
> 
> where we have <!ENTITY grounding 
> "http://www.daml.org/services/owl-s/1.1/Grounding.owl">
> 
> Now, the question is, should xml:base URIs have the # in the 
> end? In the examples in the OWL Web Ontology Language Guide 
> (http://www.w3.org/TR/2004/REC-owl-guide-20040210/),
> they do. For example:
> 
> xml:base  ="http://www.w3.org/TR/2004/REC-owl-guide-20040210/wine#"
> 
> Are these examples wrong? A lot of things suggest that they are.
> 
> 
> First, in the OWL Web Ontology Language Reference 
> (http://www.w3.org/TR/owl-ref/), Appendix A, the owl ontology 
> itself has:
> 
> xml:base  ="http://www.w3.org/2002/07/owl"
> (no # in the end).
> 
> 
> The OWL Ref says that
> 
> "The line
> 
>   <owl:Ontology rdf:about="">
> 
> states that this block describes the current ontology. More 
> precisely, it states the current base URI identifies an 
> instance of the class 
> |owl:Ontology|. It is recommended that the base URI be 
> defined using an 
> |xml:base| attribute in the |<rdf:RDF>| element at the 
> beginning of the
> document."
> 
> and the OWL Guide that
> 
> "The rdf:about attribute provides a name or reference for the 
> ontology.
> Where the value of the attribute is "", the standard case, the 
> name of the ontology is the base URI of the owl:Ontology element.  
> Typically, this is the URI of the document containing the ontology.
> An exception to this is a context that makes use of xml:base 
> which may set the base URI for an element to something other than the
> URI of the current document."
> 
> I guess this still doesn't give conclusive evidence for 
> either variant. But if we consider that
> "Syntactically, |owl:imports| is a property with the class 
> |owl:Ontology| as its domain and range" (OWL Ref) *and* 
> that the URI given to owl:imports is written _without_ the # 
> (at least I have never seen it _with_ a #), *and*
> that the xml:base gives the URI to the owl:Ontology instance, 
> then it looks like the xml:base should be
> written _without_ the #. Thus, the examples in the OWL Guide 
> would be wrong.
> 
> What do you think?
> 
> /Daniel
> 
> 
Received on Sunday, 17 October 2004 08:01:18 GMT

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