RE: Restrictions on property chains

Hello,

Oops, that's a big omission -- sorry! I've just fixed it, and here is the diff:

http://www.w3.org/2007/OWL/wiki/index.php?title=Syntax&diff=13356&oldid=13230

Uli and Ian, could you please go again over the restrictions and make sure that I haven't overlooked anything else?

Regards,

	Boris

> -----Original Message-----
> From: public-owl-wg-request@w3.org [mailto:public-owl-wg-request@w3.org] On Behalf Of Evren Sirin
> Sent: 24 September 2008 15:30
> To: Web Ontology Language ((OWL)) Working Group WG
> Subject: Restrictions on property chains
> 
> 
> I'm comparing the restrictions defined in the syntax document
> regarding property chains [1] and the conditions defined in the SROIQ
> paper [2]. I'm having problems verifying they enforce actually the
> same conditions.
> 
> In [2], it is said that there should be a regular order on the set of
> properties which is defined to be a strict partial order with the
> additional restriction that
> 
> S < R iff INV(S) < R
> 
> In [1], the strict partial order requirement is there but I don't see
> anything that would enforce this additional constraint. As a result,
> an axiom like
> 
> SubPropertyOf( PropertyChain( P P ) InverseOf( P ) )
> 
> is disallowed by [2] but allowed by [1].
> 
> Is this difference in the definitions because regularity was more
> strict than necessary? Or is this a bug in [2]?
> 
> Regards,
> Evren
> 
> PS: A very minor issue is that the citation [3] is for [2] but link
> points to the technical report [4].
> 
> [1] http://www.w3.org/2007/OWL/wiki/Syntax#The_Restrictions_on_the_Axiom_Closure
> [2] http://www.cs.man.ac.uk/~sattler/publications/KR-06-SROIQ.pdf
> [3] http://www.w3.org/2007/OWL/wiki/Syntax#ref-sroiq
> [4] http://www.cs.man.ac.uk/~sattler/publications/sroiq-TR.pdf