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Re: formal expression of property chains

From: Alistair Miles <alistair.miles@zoo.ox.ac.uk>
Date: Tue, 12 May 2009 10:36:42 +0100
To: Thomas Bandholtz <thomas.bandholtz@innoq.com>
Cc: public-esw-thes@w3.org
Message-ID: <20090512093642.GB7571@skiathos>
Hi Thomas,

To formally state property chain axioms, you need OWL 2. Because OWL 2
is not a W3C Recommendation yet, we have not used any OWL 2 features in
the SKOS RDF schema. Antoine has experimented with this (see [1]), but
it's unofficial as yet.

You can get the desired inference via other means, e.g., procedurally,
or via some inference rules.

E.g. as forward rules using the Jena rule syntax [2]:

# Jena rules for SKOS-XL to vanilla SKOS labeling property dumb-down

@prefix skos: <http://www.w3.org/2004/02/skos/core#>.
@prefix skosxl: <http://www.w3.org/2008/05/skos-xl#>.

[S55: (?x skosxl:prefLabel ?y) (?y skosxl:literalForm ?z) -> (?x skos:prefLabel ?z)]
[S56: (?x skosxl:altLabel ?y) (?y skosxl:literalForm ?z) -> (?x skos:altLabel ?z)]
[S57: (?x skosxl:hiddenLabel ?y) (?y skosxl:literalForm ?z) -> (?x skos:hiddenLabel ?z)]

Hth,

Alistair

[1] http://lists.w3.org/Archives/Public/public-swd-wg/2009Mar/0043.html
[2] http://jena.sourceforge.net/inference/#rules

On Tue, May 12, 2009 at 08:54:34AM +0200, Thomas Bandholtz wrote:
> Hy,
> 
> looking at the property chain definitions (S 55-57) in
> http://www.w3.org/TR/skos-reference/#xl-labels,
> I cannot find them in the formal RDF of skosxl.
> 
> Primer says:
> http://www.w3.org/TR/2008/WD-skos-primer-20080829/#secrelationshipslabels
> "If an instance of xl:Label is attached to a concept by, say, a
> skos-xl:altLabel statement, it follows from the SKOS-XL semantics that
> the literal form of the xl:Label instance is related to this concept by
> a standard skos:altLabel statement. In the above example, ex:FAO
> therefore has "FAO"@en" as alternative (literal) label."
> 
> How can any RDF tool behave like that and display skosxl:literalForm
> "FAO" in this example just like it would display the direct literal of a
> skos:altLabel?
> 
> Are these semantics informal?
> Did I miss something?
> 
> Kind regards,
> Thomas
> 
> -- 
> Thomas Bandholtz, thomas.bandholtz@innoq.com, http://www.innoq.com
> innoQ Deutschland GmbH, Halskestr. 17, D-40880 Ratingen, Germany
> Phone: +49 228 9288490 Mobile: +49 178 4049387 Fax: +49 2102 77160-1
> 
> 
> 

-- 
Alistair Miles
Senior Computing Officer
Image Bioinformatics Research Group
Department of Zoology
The Tinbergen Building
University of Oxford
South Parks Road
Oxford
OX1 3PS
United Kingdom
Web: http://purl.org/net/aliman
Email: alistair.miles@zoo.ox.ac.uk
Tel: +44 (0)1865 281993
Received on Tuesday, 12 May 2009 09:37:20 GMT

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