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Review of mapping rules and informal description

From: Jeremy Carroll <jjc@hpl.hp.com>
Date: Tue, 21 Jan 2003 12:05:27 +0100
To: www-webont-wg@w3.org
Message-Id: <200301211205.27814.jjc@hpl.hp.com>


I generally agree with Herman that a rewrite of this section 4.2 would be in 
order, probably working in the opposite direction (bottom up not top down), 
and having a clear statement of which RDF graphs are OWL Lite and which are 
OWL DL (in the informal description as well as defined with the mapping 
rules).

Specifics problems that I note are:
(1) precisely the xsd datatypes used in a graph have to be declared as of type 
rdfs:Datatype - seems a little problematic to me.
(2) the restrictions on annotations are incorrect, in that they block the use 
of useufl RDFS and OWL properties which are intended as annotations.
(3) no clear identification of OWL Lite constraints
(4) owl:Thing and owl:Nothing according to the mapping rules have to be 
declared as of type owl:Class, whereas the text has them built-in
(5) interactions with RDFS schema is bad
(6) I believe that certain properties e.g. dc:creator, rdfs:comment, should be 
allowed in both annotations and individual descriptions


I will have a go today at proposed alternative text; I will start by writing 
something that I think might be intelligible and result in intelligible error 
messages, and then work backwards to propose changes in both the mapping 
rules and the abstract syntax.

More detail:

(1)

<owl:DatatypeProperty rdf:ID="p"/>
<owl:Thing>
   <eg:p rdf:datatype="&xsd;int">3</eg:p>
</owl:Thing>
<rdfs:Datatype rdf:about="&xsd;int"/>

is in OWL Lite, whereas:
neither

<owl:DatatypeProperty rdf:ID="p"/>
<owl:Thing>
   <eg:p rdf:datatype="&xsd;int">3</eg:p>
</owl:Thing>

nor

<owl:DatatypeProperty rdf:ID="p"/>
<owl:Thing>
</owl:Thing>
<rdfs:Datatype rdf:about="&xsd;int"/>

are.

(2) consider owl:backwardsCompatibleWith owl:version, owl:priorVersion etc.
Also see:
http://lists.w3.org/Archives/Public/www-webont-wg/2003Jan/0323.html

(3)

(4)
All classes must go through the mapping rule:

 classID
=>
classID rdf:type owl:Class . 

(5)
See
http://lists.w3.org/Archives/Public/www-webont-wg/2003Jan/0322.html
and
end of
http://lists.w3.org/Archives/Public/www-webont-wg/2003Jan/0328.html

(6)
Currently both:

<owl:DatatypeProperty rdf:ID="p">
  <rdfs:Label>p</rdfs:Label>
</owl:DatatypeProperty>
<owl:Thing>
   <eg:p>3</eg:p>
</owl:Thing>

and

<owl:DatatypeProperty rdf:about="&rdfs;Label"/>
<owl:DatatypeProperty rdf:ID="p"/>
<owl:Thing>
  <rdfs:Label>thing</rdfs:Label>
   <eg:p>3</eg:p>
</owl:Thing>

are legal OWL Lite, but it is not possible to combine them, e.g.

<owl:DatatypeProperty rdf:about="&rdfs;Label"/>
<owl:DatatypeProperty rdf:ID="p">
  <rdfs:Label>p</rdfs:Label>
</owl:DatatypeProperty>
<owl:Thing>
  <rdfs:Label>thing</rdfs:Label>
   <eg:p>3</eg:p>
</owl:Thing>

is OWL Full.

Jeremy
Received on Tuesday, 21 January 2003 06:05:01 GMT

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