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Re: S&AS comments

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 03 Apr 2003 13:26:27 -0500 (EST)
Message-Id: <20030403.132627.68529199.pfps@research.bell-labs.com>
To: pan@cs.man.ac.uk
Cc: www-webont-wg@w3.org

Thanks for you comments Jeff.  

Unfortunately they showed up at a time where I couldn't address them before
the last call document went out.  Could you please send a message to
public-webont-comments@w3.org that includes them so that they can be
recorded as official last-call comments?  It would be best if you changed
the introductory paragraph slightly, of course.

Thanks, 

peter


From: "Jeff Z. Pan" <pan@cs.man.ac.uk>
Subject: S&AS comments
Date: Fri, 28 Mar 2003 16:16:27 -0000

> 
> This message contains some comments on the S&AS document (26 March 2003) about
> datatypes and annotations -  it is far from being a comprehensive review though.
> 
> 1. Section 2
> 
> Section 2 claims that OWL uses some of the facilities of XML Schema, and some
> built-in XML Schema datatypes can be used in OWL. It is not clear, however,
> whether the derived datatypes based on the above supported XML Schema datatypes
> can be used in OWL or not. Reasons for why they can (or can't) be used in OWL are
> expected to be explained in section 2 as well.
> 
> 
> 2. Section 3
> 
> (1) In the definition of the formal syntax, rdf:type is treated as an annotation
> property as follows:
> 
> ER:VAP U {rdf:type} -> P(R*(R U LVT)),
> 
> while no explanation is made about why it is treated this way.
> 
> (2) The description of the elements of VD is a bit confusing, along with the
> supported datatype described in section 2. Section 2 says a list of XML Schema
> datatypes can be used in OWL, ..., *and* OWL also uses rdfs:Literal and can use
> rdf:XMLLiteral. Section 3.1 says VD contains the URI references of the built-in
> OWL datatypes and rdfs:Literal. Thus it seems that rdfs:Literal and
> rdf:XMLLiteral are not built-in OWL datatypes, and rdf:XMLLiteral is not in VD
> (but can be in D of a datatype theory). Is that right?
> 
> (3) In the definition of datatype theory, it is not clear that what kinds of
> datatypes can be in the set D. Does it contain only the built-in OWL datatypes,
> or also their derived datatypes? If it can only consist of built-in OWL
> datatypes, the datatype theory is quite limited and seems to me not enough in
> many cases.
> 
> (4) In an abstract OWL interpretation, I think it might be easier to understand,
> if we present S in the following way:
> 
> S: VI -> R
> SA: VI U VC U VD U VDP U VIP U VAP U VO U {owl:DeprecatedClass,
> owl:DeprecatedProperty} -> R U LVT
> 
> so that we won't confuse ourselves S(i),the interpretation of an individual URI,
> and SA(i), some annotation of  an individual URI. Surely S can be further
> extended to plain literals and types literals. I believe separating
> interpretation and annotation is usually a good idea.
> 
> (5) The expression EC(annotation(p1 o1)) seems to me a bit annoying, partly
> because having annotation in interpretation is strange, partly because
> annotations don't seem to be natural elements of VC or VD.
> 
> 
> Jeff
> --
> Jeff Z. Pan  ( http://DL-Web.man.ac.uk/ )
> Computer Science Dept., The University of Manchester
> 
> 
> 
> 
Received on Thursday, 3 April 2003 13:26:40 GMT

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