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RE: Punning discussion

From: Michael Schneider <schneid@fzi.de>
Date: Thu, 24 Jan 2008 11:48:27 +0100
Message-ID: <0EF30CAA69519C4CB91D01481AEA06A06C294D@judith.fzi.de>
To: "Alan Ruttenberg" <alanruttenberg@gmail.com>
Cc: "OWL Working Group WG" <public-owl-wg@w3.org>
Hi!

I couldn't attend yesterday's meeting. So I don't know what the current
state of the discussion about punning is, which means that what I say below
may already have been said. My point in this mail is about the relation
between Punning and OWL-Full, only. I may come up with another point later.

>From: Alan Ruttenberg
>Sent: Tuesday, January 22, 2008 9:21 AM

>3) [...] How does punning effect OWL Full?

Punning is a DL-only feature, and cannot affect the definition of Full, as
long as Full is understood to be an RDF compatible language. In RDF, two
occurrences of the same name denote the same entity. Full cannot be adjusted
to punning semantics without losing its compatibility to RDF's
model-theoretic semantics.

Maybe the "punning for metamodelling" usecase suggests this, but punning is
not a feature in the same sense that QCRs or IFDPs are features. The latter
can easily (at least in principle) be given proper semantics in Full,
without the danger of getting into conflict with the core RDF semantics.
Punning, however, makes more fundamental assertions about what semantical
interpretations are, by allowing the same name to denote more than one
entity. One can see this in a way that under punning semantics,
interpretations are not functions, but are more general relations (not being
restricted to having at most a single value from the relation's range for
any given value from its domain). Or, alternatively, one can imagine that
there are several unrelated interpretation functions for each syntactic
category ("I_i(.)" for individuals, "I_c(.)" for classes, etc.). Or one can
think about a single, but 2-ary interpretation function, getting both a name
and a syntactic category as its arguments. You may choose your favorite
form. :) Anyway, for RDF, the form of semantical interpretations is
specified in the RDF semantics spec [1], and it cannot be changed to a form
needed for punning (except by a future RDF-WG, of course).

The practical consequence of this consideration for this OWL-WG is, that the
definition of OWL-1.1-Full will not depend on the question, whether DL will
have punning or not.

Cheers,
Michael

[1] http://www.w3.org/TR/rdf-mt/#sinterp

--
Dipl.-Inform. Michael Schneider
FZI Forschungszentrum Informatik Karlsruhe
Abtl. Information Process Engineering (IPE)
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Email: Michael.Schneider@fzi.de
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Received on Thursday, 24 January 2008 10:48:51 GMT

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