Re: Web Rule Language - WRL vs SWRL

Jim Hendler wrote:
> 
> At 12:04 +0200 6/22/05, Jos de Bruijn wrote:
> >
> >Dreer Michael WI wrote:
> >
> >>Hello,
> >>
> >>what is the relationship between WRL and SWRL?
> >
> >Hello Michael, others,
> >
> >With WRL we take an approach different from SWRL. We build on the
> >experience in
> >the Logic Programming and Deductive Database communities (and
> >partially other rules communities) and (syntactically) restrict
> >ourselves to Horn and add nonmonotonic negation, whereas SWRL stays
> >within a First-order framework and simply extends the expressiveness
> >of OWL DL. WRL extends a subset of OWL DL; this subset which falls in
> >the framework of standard Horn rules.
> >
> >
> 
> Sorry, but this cannot be right.  SWRL assumes closed world semantics 
> and WRL assumes open world semantics.   Thus, we get completely 
> different entailments in an OWL/RDF world than in a WRL one, so we 
> are talking something very different than a subset relationship.  Ian 
> Horrocks, Peter Patel-Schneider, and Bijan Parsia (with me as a 
> kibbitzer) wrote a short paper about this available at [1]


**I believe that the mention of OWL-DL in the above message is a typo.**
The intent was DLP.

Regarding your paper, I wonder what notion of language extension are you using.
The one that I was taught as a child says:

L1 extends L0  iff  L0 \subseteq L1 and 
                    for any pair of formulas f1,f2 in L0,
	       	    f1 |= f2 in L0 if and only if f1 |= f2 in L1.

Since neither DLP not RDF has negative queries, the statement about
language extension holds for them. Of course, in this case we should use
a 1-1 homomorphism to inject L0 into L1, because DLP/RDF have different
syntax from WRL.


> Let me be clear, I'm all for Web (and Sem Web) rules languages, but 
> if it isn't open-world, I don't see how it can be Sem Web, since it 
> violates the base assumption on which all of RDF, RDFS, and OWL sit. 
> This is easily fixable, and at the Rules workshop the idea of a 
> "Scoped Negation as Failure" was developed to handle this -- I'd love 
> to see WRL (and SWRL) extended to have a SNAF mechanism, because then 
> we don't violate the basic principles of the Web architecture and the 
> Semantic Web, but we should be precise - two things with very 
> different Semantics and entailments cannot be referred to as subsets 
> of each other.

I would like to mention here that the notion of scoped negation was *NOT*
developed at that workshop. It existed before, and I don't know who first
coined it (must have been 10 years or so). This type of negation is even
implemented in some systems, like FLORA-2.  In that particular system it
exists since the end of 2000.


	--michael  


>   -JH
> 
> 
> 
> 
> [1] http://www.cs.man.ac.uk/~horrocks/Publications/download/2005/HPPH05.pdf
> 
> >Best, Jos
> >
> >>
> >>Thanks in advance
> >>
> >>Michael Dreer
> >>
> >>
> >
> >>  Steve Ross-Talbot wrote:
> >>
> >>  >>Out of curiosity and also business pragmatics what is the relationship
> >>  >>between WRL and RuleML?
> >>
> >>
> >>
> >>  RuleML provides an extensive lattice of sublanguages ranging from
> >>  production rules to regular LP rules to First-Order Logic, es well as
> >>  sublanguages with such features as slotted syntax, meta-programming, and
> >>  courteous logic programming.
> >>
> >>  WRL makes a choice to use include particular features in the language.
> >>  It turns out that these features correspond to certain RuleML
> >>  sublanguages to a great extent. Therefore, RuleML can be used for the
> >>  XML serialization of a large part of the language.
> >>
> >>  The following document describes the (RuleML and other) schemas used for
> >>  the XML serialization of WRL:
> >>
> >>  http://www.wsmo.org/wsml/wrl/wrl-xmlschemas.html
> >>
> >>  More details on the XML serialization of WRL can be found at:
> >>
> >>  http://www.wsmo.org/wsml/wrl/wrl.html#cha:wrl-xml
> >>
> >>  I hope this clarifies the issue.
> >>
> >>
> >>  Best, Jos
> >>
> >>
> >>  >>Cheers
> >>  >>
> >>  >>Steve T
> >>  >>
> >>  >>On 21 Jun 2005, at 08:28, Jos de Bruijn wrote:
> >>  >>
> >>  >>Dear all,
> >>  >>
> >>  >>On behalf of WSML, AIFB and NRCC I am pleased to announce:
> >>  >>
> >>  >>The Web Rule Language WRL - version 1.0:
> >>  >>
> >>  >>http://www.wsmo.org/wsml/wrl/
> >>  >>
> >>  >>
> >>  >>WRL is a rule language for the Web and the Semantic Web and was
> >>  >>heavily influenced by the Web Service Modeling Language WSML
> >>  >>(http://www.wsmo.org/wsml/wsml-syntax).
> >>  >>
> >>  >>
> >>  >>Best regards,
> >>  >>
> >>  >>Jos de Bruijn
> >>  >>
> >>  >>>>
> >>  >>>>
> >>
> >>
> >>  --
> >>  Jos de Bruijn, http://www.uibk.ac.at/~c703239/
> >>  +43 512 507 6475 jos.debruijn@deri.org
> >>
> >>  DERI http://www.deri.org/
> >>  ----------------------------------------------
> >>
> >>  Only two things are infinite, the universe and
> >>  human stupidity, and I'm not sure about the
> >>  former.
> >>  -- Albert Einstein
> >
> >
> >- --
> >Jos de Bruijn, http://www.uibk.ac.at/~c703239/
> >+43 512 507 6475         jos.debruijn@deri.org
> >
> >DERI                      http://www.deri.org/
> >- ----------------------------------------------
> >
> >Only two things are infinite, the universe and
> >human stupidity, and I'm not sure about the
> >former.
> >     -- Albert Einstein
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> 
> -- 
> Professor James Hendler			  Director
> Joint Institute for Knowledge Discovery	  	  301-405-2696
> UMIACS, Univ of Maryland			  301-314-9734 (Fax)
> College Park, MD 20742	 		  http://www.cs.umd.edu/users/hendler
> 
>

Received on Wednesday, 22 June 2005 15:16:14 UTC