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From: Danny Ayers <danny666@virgilio.it>
Date: Sun, 3 Nov 2002 12:18:03 +0100
To: "RDF-Interest" <www-rdf-interest@w3.org>, <xfml@yahoogroups.com>
Message-ID: <EBEPLGMHCDOJJJPCFHEFGEPGIEAA.danny666@virgilio.it>

A list crossover post, I think the intersection raises interesting questions
on both sides.

XFML (eXchangable Faceted Metadata Language) is a lightweight language for
classification, which draws largely from the Topic Map tradition. The
representation of this information in RDF could I think be very useful (the
language is already in use for syndication feeds - see the purple icon at
the bottom of [6]). Below is a description of the key term in this language,
and my initial thoughts looking at it from an RDF point of view.

There is a public space for discussion of this that doesn't involve getting
tangled up with the mailing lists - the XFML Wiki [4].


from [2]:
Facets are mutually exclusive containers that contain hierarchies of topics.

Mutually exclusive means that a certain topic can only possibly belong to
one facet. "Things to do" and "Places to go" are good facets, because a
topic can never be both a thing to do and a place to go to. "People" and
"Colours" are two other good facets. "Cities" and "Places to visit" are bad
facets if used in the same map because "Brussels" (a potential topic) could
belong to both. Note that the "mutually exclusive" requirement is not
something that can be enforced by software.

My first impression is that the facets can't be expressed in vanilla RDF
because of the mutual exclusion requirement. However, the DAML+OIL language
[3] (and its forthcoming successor, OWL [7] (not Lite)) contains
daml:disjointWith, so I think facet could probably be expressed as a class
through this. Apart from the 'facet' term itself, I think everything else
can be expressed fairly easily in RDF(S), mostly following existing XTM/RDF
mappings [5].

There may still be problems in regards to the open/closed world assumptions
and the extent of the exclusivity (I'm not quite clear enough in my
understanding of XFML or logic!).

[1] http://xfml.org/
[2] http://www.xfml.org/spec/1.0.html
[3] http://www.w3.org/TR/daml+oil-reference
[4] http://xfml.net/index.php?page=XfmlAndRDF
[5] http://www.w3.org/2002/06/09-RDF-topic-maps/
[6] http://www.iaslash.org/module.php?mod=syndication
[7] http://www.w3.org/2001/sw/WebOnt/

Danny Ayers

Idea maps for the Semantic Web

<stuff> http://www.isacat.net </stuff>

Semantic Web Log :
Received on Sunday, 3 November 2002 06:28:33 UTC

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