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RE: Semantics of antisymmetric properties

From: Boris Motik <bmotik@cs.man.ac.uk>
Date: Mon, 12 Mar 2007 15:31:52 -0000
To: "'Michael Schneider'" <m_schnei@gmx.de>, <gstoil@image.ece.ntua.gr>
Cc: <evren@clarkparsia.com>, <public-owl-dev@w3.org>
Message-ID: <004301c764bb$8ef2b080$27c35882@wolf>

Hello,

I would just like to point out an important issue: we currently don't know
how to reason with antisymmetric properties. In fact, we don't even know
whether reasoning in SROIQ with antisymmetric properties is decidable.
Hence, for the time being at least, I don't believe we have a choice other
than to rename antisymmetric into asymmetric.

Sincerely yours,

	Boris 

> -----Original Message-----
> From: Michael Schneider [mailto:m_schnei@gmx.de]
> Sent: 12 March 2007 15:24
> To: gstoil@image.ece.ntua.gr
> Cc: bmotik@cs.man.ac.uk; evren@clarkparsia.com; public-owl-dev@w3.org
> Subject: RE: Semantics of antisymmetric properties
> 
> Giorgos Stoilos wrote on Mon, 12 Mar 2007:
> 
> > I guess the true question is "what semantics where really meant to be
> > captured"? Those of asymmetric or antisymmetric properties?
> 
> My opinion: I would prefer /antisymmetric/ properties (from "x p y" and
> "y p x" follows "x=y"). Then, to model some real asymmetric property
> like e.g. 'hasFather', I can easily add a "IrreflexiveObjectProperty"
> axiom to the ontology. On the other hand, I then do not get into
> problems with properties like 'locatedIn', where it could be ok to say
> that some 'Location' is 'locatedIn' itself. Adding a global
> 'ReflexiveObjectProperty' axiom to the ontology or define some local
> 'SelfRestriction' for the 'Location' class on that property would then
> be consistent.
> 
> Cheers,
> Michael
> 
> > And moreover,
> > which semantics are the implementations supporting at this point?
> Checking
> > with the reasoning algorithm in the SROIQ paper I get the feeling that
> it
> > was meant to capture antisymmetric and not asymmetric properties. Thus,
> it
> > might be a mistake on the semantics and not on the name of them.
> >
> > Best,
> > G. Stoilos
> >
> >> -----Original Message-----
> >> From: public-owl-dev-request@w3.org [mailto:public-owl-dev-
> request@w3.org]
> >> On Behalf Of Boris Motik
> >> Sent: Thursday, March 08, 2007 11:11 AM
> >> To: 'Evren Sirin'; public-owl-dev@w3.org
> >> Subject: RE: Semantics of antisymmetric properties
> >>
> >>
> >> Hello,
> >>
> >> You are right; this is a kind of a bug. Namely, we have followed the
> SROIQ
> >> paper, in which they say "antisymmetric", but the definition of the
> >> semantics is exactly as in OWL 1.1. Probably we should change the spec
> to
> >> call such properties asymmetric instead of antisymmetric.
> >>
> >> Sincerely yours,
> >>
> >> 	Boris
Received on Monday, 12 March 2007 15:32:50 GMT

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