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Re: [SKOS] Resolutions on concept semantics

From: Quentin Reul <qreul@csd.abdn.ac.uk>
Date: Tue, 30 Oct 2007 10:53:03 +0000
Message-ID: <47270D0F.1030308@csd.abdn.ac.uk>
To: SWD WG <public-swd-wg@w3.org>

I do agree with the *saying nothing* stance as I see two different 
aspect to SKOS. On the one hand, SKOS construct (like skos:prefLabel) 
can enhance a OWL ontology by adding extra information rather than using 
  rdfs:comment. However, certain aspects like skos:broader and 
skos:narrower shouldn't be applied to to owl:Class. On the other hand, 
SKOS is used to represent legacy thesaurus and dictionaries in 
skos:ConceptScheme which should be different and shouldn't include OWL 

These comments are based on my understanding that OWL ontologies are 
more complex than thesaurus.



Antoine Isaac wrote:
> It seems there are several interpretations of "saying nothing" here...
> To me saying nothing on the disjointness amounts to say that there are 
> not disjoint. The idea is that people can do what they want with their 
> concepts, including declaring some as classes or keeping them distinct. 
> If we have to find a common denominator for these different situations, 
> then it is "non-disjointess".
> As Daniel I also don't like the idea of letting people decide whether 
> skos:concept is disjoint or not. SKOS is defined by us, and we cannot 
> have people making different interpretations of the shared SKOS 
> construct, especially when they can be conflicting.
> What users can do of course is to say that *their* SKOS concepts are 
> disjoint from owl:Class (e.g. by creating a subclass of skos:Concept 
> that is disjoint with owl:Class). But this is another story...
> Cheers,
> Antoine
>> I am opposed to *saying nothing* about disjointness between 
>> skos:Concept and owl:Class (actually, in general I'm opposed to 
>> leaving any semantics undefined in SKOS)--if you leave any semantics 
>> up to the user to decide, then you ensure people will have different 
>> meanings for the same entities and relations, making interoperability 
>> impossible.
>> Daniel
>> Quoting "Miles, AJ (Alistair)" <A.J.Miles@rl.ac.uk>:
>>> Hi Antoine,
>>>> >
>>>> > [following discussion on the OWL/SKOS patterns] ... we are not
>>>> > discussing the introduction of new properties, but the semantics of
>>>> > skos:Concept, in particular its disjointness with owl:Class
>>>> > aliman: we will not say anything about the disjointness
>>>> > sean: we should make clear that the omission is explicit
>>>>  3. RESOLUTION: skos:Concept is not disjoint with owl:Class .
>>>> Some instances of SKOS concept may be also declared (and
>>>> treated) as OWL classes, and vice versa.
>>> I thought our resolution was to *say nothing* about disjointness  
>>> between skos:Concept and owl:Class. That would give people the  
>>> freedom to interpret them as disjoint, if they want to do that, or  
>>> not, if they don't.
>>> That's what I tried to capture in:
>>> [1]  
>>> <http://www.w3.org/2006/07/SWD/wiki/SKOS/Reference/Concepts?action=recall&rev=10> 
>>>> From [1] ...
>>> "The decision to leave the formal semantics of skos:Concept  
>>> undefined has been made to allow different design patterns for using 
>>>  SKOS in combination with more formal languages such as OWL to be  
>>> explored.
>>> For example, interpreting skos:Concept and owl:Class as disjoint  
>>> classes would be consistent with the semantics of SKOS.  
>>> Alternatively, interpreting skos:Concept as a super-class of  
>>> owl:Class would also be consistent with the semantics of SKOS."
>>> Cheers,
>>> Al.

* Quentin H. Reul                        *
* PhD Research Student                   *
* Department of Computing Science        *
* University of Aberdeen, King's College *
* Room 238 in the Meston Building        *
* ABERDEEN AB24 3UE                      *
* Phone: +44 (0)1224 27 4485             *
* http://www.csd.abdn.ac.uk/~qreul       *
Received on Tuesday, 30 October 2007 10:53:31 UTC

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