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Re: RDF, RDFS, and OWL language constructs

From: Charles McCathieNevile <charles@sidar.org>
Date: Sun, 17 Apr 2005 20:04:41 +0200
To: "Hans Teijgeler" <hans.teijgeler@quicknet.nl>, semantic-web@w3.org
Message-ID: <op.spd1t3n9w5l938@researchsft>

On Sun, 17 Apr 2005 18:47:31 +0200, Hans Teijgeler  
<hans.teijgeler@quicknet.nl> wrote:

> Hi!
> For most of you back to the ABC of OWL, but new to me.
> In the OWL Web Ontology Language Overview under "1.2 Why OWL?" I read:
...
> The impression is given that OWL is the cumulation of RDF, RDFS, and
> OWL-specific "language constructs".
> Then I read "2.1 OWL Lite Synopsis" and "2.2 OWL DL and Full Synopsis",  
> and
> I understand that the language constructs listed there are all there is  
> in OWL, so with the exclusion of all-but-one of the RDF constructs and  
> seven of the 15 RDFS constructs.
> Does this mean that these excluded (or non-listed) RDF and RDFS  
> constructs
> may not be used in an OWL-compliant document, or that it is commonly not
> used but valid? What is the rationale?

Hi Hans,

There are some RDF and RDFS things that are not in OWL Lite or OWL DL  
(which are just defined as subsets of OWL which don't include those things  
:-)

Full OWL is OWL that doesn't have any restriction. As I understand it the  
restriction is because if you have something that conforms to OWL DL there  
is more predictability about the logical implications that you can encode,  
and in OWL lite there is even more predictability. I believe that the big  
rationale is that you can be sure a tool that processes OWL lite won't get  
caught in some logic traps like circular definitions and undecidable  
propositions, or something like that, whereas OWL full is capable of  
encoding these kinds of statements, so processors need to be able to  
handle them.

This is a pretty rough understanding - someone with more time and  
expertise might be able to give you a more detailed explanation if you  
want one.

cheers

Chaals

-- 
Charles McCathieNevile                      Fundacion Sidar
charles@sidar.org   +61 409 134 136    http://www.sidar.org
Received on Sunday, 17 April 2005 18:04:51 UTC

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