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Re: [OWL] annotations and meta-modelling in OWL 1.1

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Mon, 09 Jan 2006 03:02:09 -0500 (EST)
Message-Id: <20060109.030209.64527517.pfps@research.bell-labs.com>
To: jpan@csd.abdn.ac.uk
Cc: Alan.Rector@manchester.ac.uk, owl@lists.mindswap.org, semantic-web@w3c.org

From: "Jeff Z. Pan" <jpan@csd.abdn.ac.uk>
Subject: Re: [OWL] annotations and meta-modelling in OWL 1.1
Date: Sun, 8 Jan 2006 20:05:20 -0000

> Hi Peter, Alan and all,
> 
> After reading Alan's following email and the proposed OWL 1.1 syntax [1], it
> seems to me that punning is not a convincing choice for metamodeling in OWL
> 1.1. ( For those who are not familiar with punning - punning means that a name,
> like Person, can be used as both an individual and a class and a property.)

Punning may not be the ideal way to proceed.  However, it is an easy way to go,
and appears to be at least somewhat useful.

> 1. It is impossible to distinguish higher order statements from annotations of
> symbols and
> artefacts we are using to represent that domain, as pointed out in Alan's
> email. The reason that they are not distinguishable is because annotations in
> [1] are simply syntactic sugar of individual axioms.

Yes, but what proposal does distinguish between higher-order statements and
annotations of symbols?

> 2. Datatype axioms, unlike other axioms in OWL 1.1 [1], cannot have
> annotations. This seems pretty strange, at least to me. The reason is that
> although individuals, object properties and classes can share names, classes
> and datatypes cannot.

>From the OWL 1.1 syntax document [1], recapitulating the OWL DL syntax:

axiom ::= 'DatatypeProperty(' datavaluedPropertyID ['Deprecated'] { annotation } 
                { 'super(' datavaluedPropertyID ')'} ['Functional']
                { 'domain(' description ')' } { 'range(' dataRange ')' } ')'

This sure looks as if datatype axioms can have annotations.

It is true that classes and datatypes cannot share names.  This could be
changed, but I don't see that it has any impact on annotations for datatype
axioms.

Perhaps you are referring to a slight ambiguity (or bug) in the OWL 1.1
syntax.  The fix would be to be more explicit about the overloading of names,
perhaps something like:

	In OWL 1.1 a name can be used as a class or datatype as well as a
	property as well as an individual.

> 3.The semantics of punning is not quite intuitive. This can be shown in the
> following example. In the following OWL 1.1 [1] ontology, Cat and Kitty are
> used as both classes and individuals. Although Cat and Kitty are the same
> individual and Ted is a Cat, the ontology
> 
> Class (Cat partial)
> Class (Kitty partial)
> SameIndividual (Cat Kitty)
> Individual (Ted Cat)
> 
> does not entail that Ted is also a Kitty. This distinguishes the punning
> semantics from many other semantics, such as the OWL FA semantics [2], Hilog
> semantics [3] and RDF semantics [4].

I do agree that the punning semantics is weaker than other semantics.  This may
make it somewhat less useful than other semantics, but does have the "benefit"
that it could be strengthened at some later date.

I disagree, however, that the semantics of punning is unintuitive.  It is just
the situation of FOL.

> Summary: 
> 
> The above point 2 suggests that the use of punning cannot really eliminate the
> need for annotations properties. 

I don't think that this is the case, and it certainly isn't a necessary feature
of OWL 1.1.

> Point 1 provides a good reason to distinguish
> annotation properties from metamodeling. 

Well, yes, but what proposal addresses this?

> Point 3 suggests that punning (as an
> option for metamodeling in OWL 1.1) is not quite intuitive and can be
> misleading.

This can be argued either way.

> Greetings,
> Jeff
> 
> [1] http://www-db.research.bell-labs.com/user/pfps/owl/syntax.html
> [2] http://dl-web.man.ac.uk/~panz/Zhilin/pubc.php?type=epapers&id=PHS05
> [3]
> http://dip.semanticweb.org/documents/Boris-Motik-On-the-Properties-of-Metamodeling-in-OWL.pdf
> [4] http://www.w3.org/TR/rdf-mt/
> 
> --
> Dr. Jeff Z. Pan (http://www.csd.abdn.ac.uk/~jpan/)
> Department of Computing Science, The University of Aberdeen


peter
Received on Monday, 9 January 2006 08:03:49 UTC

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