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[SKOS] the return of transitive and subproperty (was Re: SKOS comment: change of namespace (ISSUE-117))

From: Antoine Isaac <aisaac@few.vu.nl>
Date: Tue, 29 Jul 2008 10:30:59 +0200
Message-ID: <488ED543.2070507@few.vu.nl>
To: "Houghton,Andrew" <houghtoa@oclc.org>
CC: public-swd-wg@w3.org, public-esw-thes@w3.org

Dear Andrew,

> It also seems to me that there is a problem with this flip/flop of 
> skos:broader and skos:narrower being transitive.  SKOS now specifies 
> skos:broader and skos:narrower to be non-transitive, but 
> skos:broaderTransitive and skos:narrowerTransitive are a sub-property 
> of skos:broader and skos:narrower respectively.  This implies to me, 
> not being an RDF/OWL expert, that skos:broaderTransitive and 
> skos:narrowerTransitive inherit non-transtivity from skos:broader and 
> skos:narrower respectively, and that just seems funky since you are 
> saying that the relationship is transitive.
>

The problem of transitivity "inheritance" (or more precisely 
non-inheritance) problem has been many times raised, and many mails have 
been written about it.
Cf http://lists.w3.org/Archives/Public/public-swd-wg/2008Jun/0102.html

Now, I'm afraid we cannot do otherwise. Whatever being the naming 
decisions in the end:
- there is need non-transitive "broader-as-asserted" property (skos:broader)
- there is a need for a transitive "broader-as-get-me-all-ancestors" 
(skos:broaderTransitive)
- there is a need to infer that every asserted direct broader statement 
shall be interpreted in a way that allows to get a transitive version of 
the hierarchy (I assume that you too have this requirement)
And for the third you have no choice but to declare the first property a 
subproperty of the second. That's just the way OWL is made, even if it 
may appear counter-intuitive :-(
The nice thing is that in OWL doing so does not enforce skos:broader to 
be transitive...

Best,

Antoine
Received on Tuesday, 29 July 2008 08:31:31 GMT

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